diff --git a/lib/membership/member.ex b/lib/membership/member.ex
index 1d6d96e..6ae9307 100644
--- a/lib/membership/member.ex
+++ b/lib/membership/member.ex
@@ -5,7 +5,7 @@ defmodule Mv.Membership.Member do
   ## Overview
   Members are the core entity in the membership management system. Each member
   can have:
-  - Personal information (name, email, phone, address)
+  - Personal information (name, email, address)
   - Optional link to a User account (1:1 relationship)
   - Dynamic custom field values via CustomField system
   - Full-text searchable profile
@@ -20,9 +20,8 @@ defmodule Mv.Membership.Member do
   - `has_one :user` - Optional authentication account link
 
   ## Validations
-  - Required: first_name, last_name, email
+  - Required: email (all other fields are optional)
   - Email format validation (using EctoCommons.EmailValidator)
-  - Phone number format: international format with 6-20 digits
   - Postal code format: exactly 5 digits (German format)
   - Date validations: join_date not in future, exit_date after join_date
   - Email uniqueness: prevents conflicts with unlinked users
@@ -31,7 +30,7 @@ defmodule Mv.Membership.Member do
   Members have a `search_vector` attribute (tsvector) that is automatically
   updated via database trigger. Search includes name, email, notes, contact fields,
   and all custom field values. Custom field values are automatically included in
-  the search vector with weight 'C' (same as phone_number, city, etc.).
+  the search vector with weight 'C' (same as city, etc.).
   """
   use Ash.Resource,
     domain: Mv.Membership,
@@ -343,9 +342,7 @@ defmodule Mv.Membership.Member do
   validations do
     # Required fields are covered by allow_nil? false
 
-    # First name and last name must not be empty
-    validate present(:first_name)
-    validate present(:last_name)
+    # Email is required
     validate present(:email)
 
     # Email uniqueness check for all actions that change the email attribute
@@ -396,11 +393,6 @@ defmodule Mv.Membership.Member do
       where: [present([:join_date, :exit_date])],
       message: "cannot be before join date"
 
-    # Phone number format (only if set)
-    validate match(:phone_number, ~r/^\+?[0-9\- ]{6,20}$/),
-      where: [present(:phone_number)],
-      message: "is not a valid phone number"
-
     # Postal code format (only if set)
     validate match(:postal_code, ~r/^\d{5}$/),
       where: [present(:postal_code)],
@@ -453,12 +445,12 @@ defmodule Mv.Membership.Member do
     uuid_v7_primary_key :id
 
     attribute :first_name, :string do
-      allow_nil? false
+      allow_nil? true
       constraints min_length: 1
     end
 
     attribute :last_name, :string do
-      allow_nil? false
+      allow_nil? true
       constraints min_length: 1
     end
 
@@ -474,10 +466,6 @@ defmodule Mv.Membership.Member do
       constraints min_length: 5, max_length: 254
     end
 
-    attribute :phone_number, :string do
-      allow_nil? true
-    end
-
     attribute :join_date, :date do
       allow_nil? true
     end
@@ -1073,7 +1061,6 @@ defmodule Mv.Membership.Member do
     expr(
       contains(postal_code, ^query) or
         contains(house_number, ^query) or
-        contains(phone_number, ^query) or
         contains(email, ^query) or
         contains(city, ^query)
     )
diff --git a/lib/mv/constants.ex b/lib/mv/constants.ex
index c81dbd6..82a8400 100644
--- a/lib/mv/constants.ex
+++ b/lib/mv/constants.ex
@@ -7,7 +7,6 @@ defmodule Mv.Constants do
     :first_name,
     :last_name,
     :email,
-    :phone_number,
     :join_date,
     :exit_date,
     :notes,
diff --git a/lib/mv_web/helpers/member_helpers.ex b/lib/mv_web/helpers/member_helpers.ex
new file mode 100644
index 0000000..047bd12
--- /dev/null
+++ b/lib/mv_web/helpers/member_helpers.ex
@@ -0,0 +1,64 @@
+defmodule MvWeb.Helpers.MemberHelpers do
+  @moduledoc """
+  Helper functions for member-related operations in the web layer.
+
+  Provides utilities for formatting and displaying member information.
+  """
+
+  alias Mv.Membership.Member
+
+  @doc """
+  Returns a display name for a member.
+
+  Combines first_name and last_name if available, otherwise falls back to email.
+  This ensures that members without names still have a meaningful display name.
+
+  ## Examples
+
+      iex> member = %Member{first_name: "John", last_name: "Doe", email: "john@example.com"}
+      iex> MvWeb.Helpers.MemberHelpers.display_name(member)
+      "John Doe"
+
+      iex> member = %Member{first_name: nil, last_name: nil, email: "john@example.com"}
+      iex> MvWeb.Helpers.MemberHelpers.display_name(member)
+      "john@example.com"
+
+      iex> member = %Member{first_name: "John", last_name: nil, email: "john@example.com"}
+      iex> MvWeb.Helpers.MemberHelpers.display_name(member)
+      "John"
+  """
+  def display_name(%Member{} = member) do
+    name_parts =
+      [member.first_name, member.last_name]
+      |> Enum.reject(&blank?/1)
+      |> Enum.map_join(" ", &String.trim/1)
+
+    if name_parts == "" do
+      member.email
+    else
+      name_parts
+    end
+  end
+
+  @doc """
+  Checks if a value is blank (nil, empty string, or only whitespace).
+
+  ## Examples
+
+      iex> MvWeb.Helpers.MemberHelpers.blank?(nil)
+      true
+
+      iex> MvWeb.Helpers.MemberHelpers.blank?("")
+      true
+
+      iex> MvWeb.Helpers.MemberHelpers.blank?("   ")
+      true
+
+      iex> MvWeb.Helpers.MemberHelpers.blank?("John")
+      false
+  """
+  def blank?(nil), do: true
+  def blank?(""), do: true
+  def blank?(value) when is_binary(value), do: String.trim(value) == ""
+  def blank?(_), do: false
+end
diff --git a/lib/mv_web/live/contribution_period_live/show.ex b/lib/mv_web/live/contribution_period_live/show.ex
index 83d9207..b6a2574 100644
--- a/lib/mv_web/live/contribution_period_live/show.ex
+++ b/lib/mv_web/live/contribution_period_live/show.ex
@@ -36,7 +36,7 @@ defmodule MvWeb.ContributionPeriodLive.Show do
       <.mockup_warning />
 
       <.header>
-        {gettext("Contributions for %{name}", name: "#{@member.first_name} #{@member.last_name}")}
+        {gettext("Contributions for %{name}", name: MvWeb.Helpers.MemberHelpers.display_name(@member))}
         <:subtitle>
           {gettext("Contribution type")}:
           <span class="font-semibold">{@member.contribution_type}</span>
diff --git a/lib/mv_web/live/custom_field_value_live/form.ex b/lib/mv_web/live/custom_field_value_live/form.ex
index 9663927..4db2bed 100644
--- a/lib/mv_web/live/custom_field_value_live/form.ex
+++ b/lib/mv_web/live/custom_field_value_live/form.ex
@@ -289,6 +289,6 @@ defmodule MvWeb.CustomFieldValueLive.Form do
   end
 
   defp member_options(members) do
-    Enum.map(members, &{"#{&1.first_name} #{&1.last_name}", &1.id})
+    Enum.map(members, &{MvWeb.Helpers.MemberHelpers.display_name(&1), &1.id})
   end
 end
diff --git a/lib/mv_web/live/member_live/form.ex b/lib/mv_web/live/member_live/form.ex
index 53754aa..0a05e1f 100644
--- a/lib/mv_web/live/member_live/form.ex
+++ b/lib/mv_web/live/member_live/form.ex
@@ -43,7 +43,7 @@ defmodule MvWeb.MemberLive.Form do
 
           <h1 class="text-2xl font-bold text-center flex-1">
             <%= if @member do %>
-              {@member.first_name} {@member.last_name}
+              {MvWeb.Helpers.MemberHelpers.display_name(@member)}
             <% else %>
               {gettext("New Member")}
             <% end %>
@@ -82,10 +82,10 @@ defmodule MvWeb.MemberLive.Form do
                 <%!-- Name Row --%>
                 <div class="flex gap-4">
                   <div class="w-48">
-                    <.input field={@form[:first_name]} label={gettext("First Name")} required />
+                    <.input field={@form[:first_name]} label={gettext("First Name")} />
                   </div>
                   <div class="w-48">
-                    <.input field={@form[:last_name]} label={gettext("Last Name")} required />
+                    <.input field={@form[:last_name]} label={gettext("Last Name")} />
                   </div>
                 </div>
 
@@ -110,11 +110,6 @@ defmodule MvWeb.MemberLive.Form do
                   <.input field={@form[:email]} label={gettext("Email")} required type="email" />
                 </div>
 
-                <%!-- Phone --%>
-                <div>
-                  <.input field={@form[:phone_number]} label={gettext("Phone")} type="tel" />
-                </div>
-
                 <%!-- Membership Dates Row --%>
                 <div class="flex gap-4">
                   <div class="w-36">
diff --git a/lib/mv_web/live/member_live/index.html.heex b/lib/mv_web/live/member_live/index.html.heex
index c8ba7e4..1557ed9 100644
--- a/lib/mv_web/live/member_live/index.html.heex
+++ b/lib/mv_web/live/member_live/index.html.heex
@@ -239,24 +239,6 @@
     >
       {member.city}
     </:col>
-    <:col
-      :let={member}
-      :if={:phone_number in @member_fields_visible}
-      label={
-        ~H"""
-        <.live_component
-          module={MvWeb.Components.SortHeaderComponent}
-          id={:sort_phone_number}
-          field={:phone_number}
-          label={gettext("Phone Number")}
-          sort_field={@sort_field}
-          sort_order={@sort_order}
-        />
-        """
-      }
-    >
-      {member.phone_number}
-    </:col>
     <:col
       :let={member}
       :if={:join_date in @member_fields_visible}
diff --git a/lib/mv_web/live/member_live/show.ex b/lib/mv_web/live/member_live/show.ex
index c2af0a9..997cb1a 100644
--- a/lib/mv_web/live/member_live/show.ex
+++ b/lib/mv_web/live/member_live/show.ex
@@ -35,7 +35,7 @@ defmodule MvWeb.MemberLive.Show do
         </.button>
 
         <h1 class="text-2xl font-bold text-center flex-1">
-          {@member.first_name} {@member.last_name}
+          {MvWeb.Helpers.MemberHelpers.display_name(@member)}
         </h1>
 
         <.button variant="primary" navigate={~p"/members/#{@member}/edit?return_to=show"}>
@@ -104,11 +104,6 @@ defmodule MvWeb.MemberLive.Show do
                   </.data_field>
                 </div>
 
-                <%!-- Phone --%>
-                <div>
-                  <.data_field label={gettext("Phone")} value={@member.phone_number} />
-                </div>
-
                 <%!-- Membership Dates Row --%>
                 <div class="flex gap-6">
                   <.data_field
diff --git a/lib/mv_web/live/user_live/form.ex b/lib/mv_web/live/user_live/form.ex
index 0639e75..f0cc1ce 100644
--- a/lib/mv_web/live/user_live/form.ex
+++ b/lib/mv_web/live/user_live/form.ex
@@ -131,7 +131,7 @@ defmodule MvWeb.UserLive.Form do
               <div class="flex items-center justify-between">
                 <div>
                   <p class="font-medium text-green-900">
-                    {@user.member.first_name} {@user.member.last_name}
+                    {MvWeb.Helpers.MemberHelpers.display_name(@user.member)}
                   </p>
                   <p class="text-sm text-green-700">{@user.member.email}</p>
                 </div>
@@ -210,7 +210,7 @@ defmodule MvWeb.UserLive.Form do
                           )
                         ]}
                       >
-                        <p class="font-medium">{member.first_name} {member.last_name}</p>
+                        <p class="font-medium">{MvWeb.Helpers.MemberHelpers.display_name(member)}</p>
                         <p class="text-sm text-base-content/70">{member.email}</p>
                       </div>
                     <% end %>
@@ -438,7 +438,7 @@ defmodule MvWeb.UserLive.Form do
 
     member_name =
       if selected_member,
-        do: "#{selected_member.first_name} #{selected_member.last_name}",
+        do: MvWeb.Helpers.MemberHelpers.display_name(selected_member),
         else: ""
 
     # Store the selected member ID and name in socket state and clear unlink flag
diff --git a/lib/mv_web/live/user_live/index.html.heex b/lib/mv_web/live/user_live/index.html.heex
index 9a98159..e7fd72e 100644
--- a/lib/mv_web/live/user_live/index.html.heex
+++ b/lib/mv_web/live/user_live/index.html.heex
@@ -51,7 +51,7 @@
     </:col>
     <:col :let={user} label={gettext("Linked Member")}>
       <%= if user.member do %>
-        {user.member.first_name} {user.member.last_name}
+        {MvWeb.Helpers.MemberHelpers.display_name(user.member)}
       <% else %>
         <span class="text-base-content/50">{gettext("No member linked")}</span>
       <% end %>
diff --git a/lib/mv_web/live/user_live/show.ex b/lib/mv_web/live/user_live/show.ex
index 777def1..9eaa4fa 100644
--- a/lib/mv_web/live/user_live/show.ex
+++ b/lib/mv_web/live/user_live/show.ex
@@ -57,7 +57,7 @@ defmodule MvWeb.UserLive.Show do
               class="text-blue-600 underline hover:text-blue-800"
             >
               <.icon name="hero-users" class="inline w-4 h-4 mr-1" />
-              {@user.member.first_name} {@user.member.last_name}
+              {MvWeb.Helpers.MemberHelpers.display_name(@user.member)}
             </.link>
           <% else %>
             <span class="italic text-gray-500">{gettext("No member linked")}</span>
diff --git a/lib/mv_web/translations/member_fields.ex b/lib/mv_web/translations/member_fields.ex
index f10e0d2..2d6834a 100644
--- a/lib/mv_web/translations/member_fields.ex
+++ b/lib/mv_web/translations/member_fields.ex
@@ -20,7 +20,6 @@ defmodule MvWeb.Translations.MemberFields do
   def label(:first_name), do: gettext("First Name")
   def label(:last_name), do: gettext("Last Name")
   def label(:email), do: gettext("Email")
-  def label(:phone_number), do: gettext("Phone")
   def label(:join_date), do: gettext("Join Date")
   def label(:exit_date), do: gettext("Exit Date")
   def label(:notes), do: gettext("Notes")
diff --git a/priv/gettext/de/LC_MESSAGES/default.po b/priv/gettext/de/LC_MESSAGES/default.po
index ef28ae8..9467ed7 100644
--- a/priv/gettext/de/LC_MESSAGES/default.po
+++ b/priv/gettext/de/LC_MESSAGES/default.po
@@ -150,11 +150,6 @@ msgstr "Notizen"
 msgid "Paid"
 msgstr "Bezahlt"
 
-#: lib/mv_web/live/member_live/index.html.heex
-#, elixir-autogen, elixir-format
-msgid "Phone Number"
-msgstr "Telefonnummer"
-
 #: lib/mv_web/live/member_live/form.ex
 #: lib/mv_web/live/member_live/index.html.heex
 #: lib/mv_web/translations/member_fields.ex
@@ -842,13 +837,6 @@ msgstr "Zahlungen"
 msgid "Personal Data"
 msgstr "Persönliche Daten"
 
-#: lib/mv_web/live/member_live/form.ex
-#: lib/mv_web/live/member_live/show.ex
-#: lib/mv_web/translations/member_fields.ex
-#, elixir-autogen, elixir-format
-msgid "Phone"
-msgstr "Telefon"
-
 #: lib/mv_web/live/member_live/form.ex
 #: lib/mv_web/live/member_live/show/membership_fees_component.ex
 #, elixir-autogen, elixir-format
@@ -1903,6 +1891,18 @@ msgstr "Nicht gesetzt"
 #~ msgid "Pending"
 #~ msgstr "Ausstehend"
 
+#~ #: lib/mv_web/live/member_live/form.ex
+#~ #: lib/mv_web/live/member_live/show.ex
+#~ #: lib/mv_web/translations/member_fields.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Phone"
+#~ msgstr "Telefon"
+
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Phone Number"
+#~ msgstr "Telefonnummer"
+
 #~ #: lib/mv_web/live/contribution_settings_live.ex
 #~ #, elixir-autogen, elixir-format
 #~ msgid "Quarterly Interval - Joining Period Excluded"
diff --git a/priv/gettext/default.pot b/priv/gettext/default.pot
index be36eb6..77931d4 100644
--- a/priv/gettext/default.pot
+++ b/priv/gettext/default.pot
@@ -151,11 +151,6 @@ msgstr ""
 msgid "Paid"
 msgstr ""
 
-#: lib/mv_web/live/member_live/index.html.heex
-#, elixir-autogen, elixir-format
-msgid "Phone Number"
-msgstr ""
-
 #: lib/mv_web/live/member_live/form.ex
 #: lib/mv_web/live/member_live/index.html.heex
 #: lib/mv_web/translations/member_fields.ex
@@ -843,13 +838,6 @@ msgstr ""
 msgid "Personal Data"
 msgstr ""
 
-#: lib/mv_web/live/member_live/form.ex
-#: lib/mv_web/live/member_live/show.ex
-#: lib/mv_web/translations/member_fields.ex
-#, elixir-autogen, elixir-format
-msgid "Phone"
-msgstr ""
-
 #: lib/mv_web/live/member_live/form.ex
 #: lib/mv_web/live/member_live/show/membership_fees_component.ex
 #, elixir-autogen, elixir-format
diff --git a/priv/gettext/en/LC_MESSAGES/default.po b/priv/gettext/en/LC_MESSAGES/default.po
index 9c2dc9a..5846f7b 100644
--- a/priv/gettext/en/LC_MESSAGES/default.po
+++ b/priv/gettext/en/LC_MESSAGES/default.po
@@ -151,11 +151,6 @@ msgstr ""
 msgid "Paid"
 msgstr ""
 
-#: lib/mv_web/live/member_live/index.html.heex
-#, elixir-autogen, elixir-format
-msgid "Phone Number"
-msgstr ""
-
 #: lib/mv_web/live/member_live/form.ex
 #: lib/mv_web/live/member_live/index.html.heex
 #: lib/mv_web/translations/member_fields.ex
@@ -843,13 +838,6 @@ msgstr ""
 msgid "Personal Data"
 msgstr ""
 
-#: lib/mv_web/live/member_live/form.ex
-#: lib/mv_web/live/member_live/show.ex
-#: lib/mv_web/translations/member_fields.ex
-#, elixir-autogen, elixir-format, fuzzy
-msgid "Phone"
-msgstr ""
-
 #: lib/mv_web/live/member_live/form.ex
 #: lib/mv_web/live/member_live/show/membership_fees_component.ex
 #, elixir-autogen, elixir-format, fuzzy
@@ -1827,46 +1815,62 @@ msgstr ""
 msgid "Not set"
 msgstr ""
 
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Show current cycle"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Unpaid in last cycle"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/custom_field_live/index_component.ex
+#~ #, elixir-autogen, elixir-format, fuzzy
+#~ msgid "New Custom field"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Show Last/Current Cycle Payment Status"
+#~ msgstr ""
+
 #~ #: lib/mv_web/live/components/payment_filter_component.ex
 #~ #, elixir-autogen, elixir-format
 #~ msgid "All payment statuses"
 #~ msgstr ""
 
-#~ #: lib/mv_web/live/custom_field_live/show.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Auto-generated identifier (immutable)"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/contribution_settings_live.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Configure global settings for membership contributions."
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/form.ex
-#~ #: lib/mv_web/live/member_live/show.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Contribution"
-#~ msgstr ""
-
-#~ #: lib/mv_web/components/layouts/navbar.ex
-#~ #: lib/mv_web/live/contribution_settings_live.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Contribution Settings"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/contribution_settings_live.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Contribution start"
-#~ msgstr ""
-
 #~ #: lib/mv_web/live/member_live/index.html.heex
 #~ #, elixir-autogen, elixir-format
 #~ msgid "Copy emails"
 #~ msgstr ""
 
+#~ #: lib/mv_web/live/member_live/form.ex
+#~ #: lib/mv_web/live/member_live/show.ex
+#~ #: lib/mv_web/translations/member_fields.ex
+#~ #, elixir-autogen, elixir-format, fuzzy
+#~ msgid "Phone"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/show.ex
+#~ #, elixir-autogen, elixir-format, fuzzy
+#~ msgid "Pending"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/show.ex
+#~ #, elixir-autogen, elixir-format, fuzzy
+#~ msgid "Payment Cycle"
+#~ msgstr ""
+
 #~ #: lib/mv_web/live/contribution_settings_live.ex
 #~ #, elixir-autogen, elixir-format
-#~ msgid "Default Contribution Type"
+#~ msgid "View Example Member"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/form.ex
+#~ #: lib/mv_web/live/member_live/show.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "This data is for demonstration purposes only (mockup)."
 #~ msgstr ""
 
 #~ #: lib/mv_web/live/contribution_settings_live.ex
@@ -1875,6 +1879,11 @@ msgstr ""
 #~ msgid "Edit amount"
 #~ msgstr ""
 
+#~ #: lib/mv_web/live/contribution_settings_live.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Quarterly Interval - Joining Period Excluded"
+#~ msgstr ""
+
 #~ #: lib/mv_web/live/contribution_settings_live.ex
 #~ #, elixir-autogen, elixir-format
 #~ msgid "Example: Member Contribution View"
@@ -1885,20 +1894,20 @@ msgstr ""
 #~ msgid "Failed to delete some cycles: %{errors}"
 #~ msgstr ""
 
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Switch to current cycle"
+#~ msgstr ""
+
 #~ #: lib/mv_web/live/membership_fee_settings_live.ex
 #~ #, elixir-autogen, elixir-format
 #~ msgid "Failed to save settings. Please check the errors below."
 #~ msgstr ""
 
-#~ #: lib/mv_web/live/user_live/index.html.heex
-#~ #: lib/mv_web/live/user_live/show.ex
+#~ #: lib/mv_web/components/layouts/navbar.ex
+#~ #: lib/mv_web/live/contribution_settings_live.ex
 #~ #, elixir-autogen, elixir-format
-#~ msgid "Generated periods"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/custom_field_live/form_component.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Immutable"
+#~ msgid "Contribution Settings"
 #~ msgstr ""
 
 #~ #: lib/mv_web/live/contribution_settings_live.ex
@@ -1906,80 +1915,9 @@ msgstr ""
 #~ msgid "Include joining period"
 #~ msgstr ""
 
-#~ #: lib/mv_web/live/custom_field_live/index_component.ex
-#~ #, elixir-autogen, elixir-format, fuzzy
-#~ msgid "New Custom field"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/components/payment_filter_component.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Not paid"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/show.ex
-#~ #, elixir-autogen, elixir-format, fuzzy
-#~ msgid "Payment Cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/show.ex
-#~ #, elixir-autogen, elixir-format, fuzzy
-#~ msgid "Pending"
-#~ msgstr ""
-
 #~ #: lib/mv_web/live/contribution_settings_live.ex
 #~ #, elixir-autogen, elixir-format
-#~ msgid "Quarterly Interval - Joining Period Excluded"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Show Last/Current Cycle Payment Status"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Show current cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Show last completed cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Switch to current cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Switch to last completed cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/form.ex
-#~ #: lib/mv_web/live/member_live/show.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "This data is for demonstration purposes only (mockup)."
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Unpaid in current cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/member_live/index.html.heex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Unpaid in last cycle"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/contribution_settings_live.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "View Example Member"
-#~ msgstr ""
-
-#~ #: lib/mv_web/live/contribution_settings_live.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "Yearly Interval - Joining Period Included"
+#~ msgid "Contribution start"
 #~ msgstr ""
 
 #~ #: lib/mv_web/live/member_live/form.ex
@@ -1988,7 +1926,69 @@ msgstr ""
 #~ msgid "monthly"
 #~ msgstr ""
 
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Show last completed cycle"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/components/payment_filter_component.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Not paid"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/contribution_settings_live.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Yearly Interval - Joining Period Included"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/custom_field_live/form_component.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Immutable"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/form.ex
+#~ #: lib/mv_web/live/member_live/show.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Contribution"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/user_live/index.html.heex
+#~ #: lib/mv_web/live/user_live/show.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Generated periods"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Switch to last completed cycle"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/contribution_settings_live.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Configure global settings for membership contributions."
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/custom_field_live/show.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Auto-generated identifier (immutable)"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/contribution_settings_live.ex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Default Contribution Type"
+#~ msgstr ""
+
 #~ #: lib/mv_web/live/member_live/form.ex
 #~ #, elixir-autogen, elixir-format
 #~ msgid "yearly"
 #~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Phone Number"
+#~ msgstr ""
+
+#~ #: lib/mv_web/live/member_live/index.html.heex
+#~ #, elixir-autogen, elixir-format
+#~ msgid "Unpaid in current cycle"
+#~ msgstr ""
diff --git a/priv/repo/migrations/20260102155350_remove_phone_number_and_make_fields_optional.exs b/priv/repo/migrations/20260102155350_remove_phone_number_and_make_fields_optional.exs
new file mode 100644
index 0000000..5943b78
--- /dev/null
+++ b/priv/repo/migrations/20260102155350_remove_phone_number_and_make_fields_optional.exs
@@ -0,0 +1,404 @@
+defmodule Mv.Repo.Migrations.RemovePhoneNumberAndMakeFieldsOptional do
+  @moduledoc """
+  Removes phone_number field from members table and makes first_name/last_name optional.
+
+  This migration:
+  1. Removes phone_number column from members table
+  2. Makes first_name and last_name columns nullable
+  3. Updates members_search_vector_trigger() function to remove phone_number
+  4. Updates update_member_search_vector_from_custom_field_value() function to remove phone_number
+  5. Updates existing search_vector values for all members
+  """
+
+  use Ecto.Migration
+
+  def up do
+    # Update the main trigger function to remove phone_number
+    execute("""
+    CREATE OR REPLACE FUNCTION members_search_vector_trigger() RETURNS trigger AS $$
+    DECLARE
+      custom_values_text text;
+    BEGIN
+      -- Aggregate all custom field values for this member
+      -- Support both formats: _union_type/_union_value (Ash format) and type/value (legacy)
+      -- ->> operator always returns TEXT directly (no need for -> + ::text fallback)
+      SELECT string_agg(
+        CASE
+          WHEN value ? '_union_value' THEN value->>'_union_value'
+          WHEN value ? 'value' THEN value->>'value'
+          ELSE ''
+        END,
+        ' '
+      )
+      INTO custom_values_text
+      FROM custom_field_values
+      WHERE member_id = NEW.id AND value IS NOT NULL;
+
+      -- Build search_vector with member fields and custom field values
+      NEW.search_vector :=
+        setweight(to_tsvector('simple', coalesce(NEW.first_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(NEW.last_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(NEW.email, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(NEW.join_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(NEW.exit_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(NEW.notes, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(NEW.city, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.street, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.house_number::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.postal_code::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(custom_values_text, '')), 'C');
+      RETURN NEW;
+    END
+    $$ LANGUAGE plpgsql;
+    """)
+
+    # Update trigger function to remove phone_number
+    execute("""
+    CREATE OR REPLACE FUNCTION update_member_search_vector_from_custom_field_value() RETURNS trigger AS $$
+    DECLARE
+      member_id_val uuid;
+      member_first_name text;
+      member_last_name text;
+      member_email text;
+      member_join_date date;
+      member_exit_date date;
+      member_notes text;
+      member_city text;
+      member_street text;
+      member_house_number text;
+      member_postal_code text;
+      custom_values_text text;
+      old_value_text text;
+      new_value_text text;
+    BEGIN
+      -- Get member ID from trigger context
+      member_id_val := COALESCE(NEW.member_id, OLD.member_id);
+
+      -- Optimization: For UPDATE operations, check if value actually changed
+      -- If value hasn't changed, we can skip the expensive re-aggregation
+      IF TG_OP = 'UPDATE' THEN
+        -- Extract OLD value for comparison (handle both JSONB formats)
+        -- ->> operator always returns TEXT directly
+        old_value_text := COALESCE(
+          NULLIF(OLD.value->>'_union_value', ''),
+          NULLIF(OLD.value->>'value', ''),
+          ''
+        );
+
+        -- Extract NEW value for comparison (handle both JSONB formats)
+        new_value_text := COALESCE(
+          NULLIF(NEW.value->>'_union_value', ''),
+          NULLIF(NEW.value->>'value', ''),
+          ''
+        );
+
+        -- Check if value, member_id, or custom_field_id actually changed
+        -- If nothing changed, skip expensive re-aggregation
+        IF (old_value_text IS NOT DISTINCT FROM new_value_text) AND
+           (OLD.member_id IS NOT DISTINCT FROM NEW.member_id) AND
+           (OLD.custom_field_id IS NOT DISTINCT FROM NEW.custom_field_id) THEN
+          RETURN COALESCE(NEW, OLD);
+        END IF;
+      END IF;
+
+      -- Fetch only required fields instead of full record (performance optimization)
+      SELECT
+        first_name,
+        last_name,
+        email,
+        join_date,
+        exit_date,
+        notes,
+        city,
+        street,
+        house_number,
+        postal_code
+      INTO
+        member_first_name,
+        member_last_name,
+        member_email,
+        member_join_date,
+        member_exit_date,
+        member_notes,
+        member_city,
+        member_street,
+        member_house_number,
+        member_postal_code
+      FROM members
+      WHERE id = member_id_val;
+
+      -- Aggregate all custom field values for this member
+      -- Support both formats: _union_type/_union_value (Ash format) and type/value (legacy)
+      -- ->> operator always returns TEXT directly
+      SELECT string_agg(
+        CASE
+          WHEN value ? '_union_value' THEN value->>'_union_value'
+          WHEN value ? 'value' THEN value->>'value'
+          ELSE ''
+        END,
+        ' '
+      )
+      INTO custom_values_text
+      FROM custom_field_values
+      WHERE member_id = member_id_val AND value IS NOT NULL;
+
+      -- Update the search_vector for the affected member
+      UPDATE members
+      SET search_vector =
+        setweight(to_tsvector('simple', coalesce(member_first_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(member_last_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(member_email, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(member_join_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(member_exit_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(member_notes, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(member_city, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_street, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_house_number::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_postal_code::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(custom_values_text, '')), 'C')
+      WHERE id = member_id_val;
+
+      RETURN COALESCE(NEW, OLD);
+    END
+    $$ LANGUAGE plpgsql;
+    """)
+
+    # Update existing search_vector values for all members
+    execute("""
+    UPDATE members m
+    SET search_vector =
+      setweight(to_tsvector('simple', coalesce(m.first_name, '')), 'A') ||
+      setweight(to_tsvector('simple', coalesce(m.last_name, '')), 'A') ||
+      setweight(to_tsvector('simple', coalesce(m.email, '')), 'B') ||
+      setweight(to_tsvector('simple', coalesce(m.join_date::text, '')), 'D') ||
+      setweight(to_tsvector('simple', coalesce(m.exit_date::text, '')), 'D') ||
+      setweight(to_tsvector('simple', coalesce(m.notes, '')), 'B') ||
+      setweight(to_tsvector('simple', coalesce(m.city, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.street, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.house_number::text, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.postal_code::text, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(
+        (SELECT string_agg(
+          CASE
+            WHEN value ? '_union_value' THEN value->>'_union_value'
+            WHEN value ? 'value' THEN value->>'value'
+            ELSE ''
+          END,
+          ' '
+        )
+        FROM custom_field_values
+        WHERE member_id = m.id AND value IS NOT NULL),
+        ''
+      )), 'C')
+    """)
+
+    # Make first_name and last_name nullable
+    execute("ALTER TABLE members ALTER COLUMN first_name DROP NOT NULL")
+    execute("ALTER TABLE members ALTER COLUMN last_name DROP NOT NULL")
+
+    # Remove phone_number column
+    alter table(:members) do
+      remove :phone_number
+    end
+  end
+
+  def down do
+    # Set default values for NULL fields before restoring NOT NULL constraint
+    # This prevents the migration from failing if NULL values exist
+    execute("UPDATE members SET first_name = '' WHERE first_name IS NULL")
+    execute("UPDATE members SET last_name = '' WHERE last_name IS NULL")
+
+    # Restore first_name and last_name as NOT NULL
+    execute("ALTER TABLE members ALTER COLUMN first_name SET NOT NULL")
+    execute("ALTER TABLE members ALTER COLUMN last_name SET NOT NULL")
+
+    # Add phone_number column back
+    alter table(:members) do
+      add :phone_number, :text
+    end
+
+    # Restore trigger functions with phone_number
+    execute("""
+    CREATE OR REPLACE FUNCTION members_search_vector_trigger() RETURNS trigger AS $$
+    DECLARE
+      custom_values_text text;
+    BEGIN
+      -- Aggregate all custom field values for this member
+      -- Support both formats: _union_type/_union_value (Ash format) and type/value (legacy)
+      -- ->> operator always returns TEXT directly (no need for -> + ::text fallback)
+      SELECT string_agg(
+        CASE
+          WHEN value ? '_union_value' THEN value->>'_union_value'
+          WHEN value ? 'value' THEN value->>'value'
+          ELSE ''
+        END,
+        ' '
+      )
+      INTO custom_values_text
+      FROM custom_field_values
+      WHERE member_id = NEW.id AND value IS NOT NULL;
+
+      -- Build search_vector with member fields and custom field values
+      NEW.search_vector :=
+        setweight(to_tsvector('simple', coalesce(NEW.first_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(NEW.last_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(NEW.email, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(NEW.phone_number, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.join_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(NEW.exit_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(NEW.notes, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(NEW.city, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.street, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.house_number::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(NEW.postal_code::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(custom_values_text, '')), 'C');
+      RETURN NEW;
+    END
+    $$ LANGUAGE plpgsql;
+    """)
+
+    execute("""
+    CREATE OR REPLACE FUNCTION update_member_search_vector_from_custom_field_value() RETURNS trigger AS $$
+    DECLARE
+      member_id_val uuid;
+      member_first_name text;
+      member_last_name text;
+      member_email text;
+      member_phone_number text;
+      member_join_date date;
+      member_exit_date date;
+      member_notes text;
+      member_city text;
+      member_street text;
+      member_house_number text;
+      member_postal_code text;
+      custom_values_text text;
+      old_value_text text;
+      new_value_text text;
+    BEGIN
+      -- Get member ID from trigger context
+      member_id_val := COALESCE(NEW.member_id, OLD.member_id);
+
+      -- Optimization: For UPDATE operations, check if value actually changed
+      -- If value hasn't changed, we can skip the expensive re-aggregation
+      IF TG_OP = 'UPDATE' THEN
+        -- Extract OLD value for comparison (handle both JSONB formats)
+        -- ->> operator always returns TEXT directly
+        old_value_text := COALESCE(
+          NULLIF(OLD.value->>'_union_value', ''),
+          NULLIF(OLD.value->>'value', ''),
+          ''
+        );
+
+        -- Extract NEW value for comparison (handle both JSONB formats)
+        new_value_text := COALESCE(
+          NULLIF(NEW.value->>'_union_value', ''),
+          NULLIF(NEW.value->>'value', ''),
+          ''
+        );
+
+        -- Check if value, member_id, or custom_field_id actually changed
+        -- If nothing changed, skip expensive re-aggregation
+        IF (old_value_text IS NOT DISTINCT FROM new_value_text) AND
+           (OLD.member_id IS NOT DISTINCT FROM NEW.member_id) AND
+           (OLD.custom_field_id IS NOT DISTINCT FROM NEW.custom_field_id) THEN
+          RETURN COALESCE(NEW, OLD);
+        END IF;
+      END IF;
+
+      -- Fetch only required fields instead of full record (performance optimization)
+      SELECT
+        first_name,
+        last_name,
+        email,
+        phone_number,
+        join_date,
+        exit_date,
+        notes,
+        city,
+        street,
+        house_number,
+        postal_code
+      INTO
+        member_first_name,
+        member_last_name,
+        member_email,
+        member_phone_number,
+        member_join_date,
+        member_exit_date,
+        member_notes,
+        member_city,
+        member_street,
+        member_house_number,
+        member_postal_code
+      FROM members
+      WHERE id = member_id_val;
+
+      -- Aggregate all custom field values for this member
+      -- Support both formats: _union_type/_union_value (Ash format) and type/value (legacy)
+      -- ->> operator always returns TEXT directly
+      SELECT string_agg(
+        CASE
+          WHEN value ? '_union_value' THEN value->>'_union_value'
+          WHEN value ? 'value' THEN value->>'value'
+          ELSE ''
+        END,
+        ' '
+      )
+      INTO custom_values_text
+      FROM custom_field_values
+      WHERE member_id = member_id_val AND value IS NOT NULL;
+
+      -- Update the search_vector for the affected member
+      UPDATE members
+      SET search_vector =
+        setweight(to_tsvector('simple', coalesce(member_first_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(member_last_name, '')), 'A') ||
+        setweight(to_tsvector('simple', coalesce(member_email, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(member_phone_number, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_join_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(member_exit_date::text, '')), 'D') ||
+        setweight(to_tsvector('simple', coalesce(member_notes, '')), 'B') ||
+        setweight(to_tsvector('simple', coalesce(member_city, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_street, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_house_number::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(member_postal_code::text, '')), 'C') ||
+        setweight(to_tsvector('simple', coalesce(custom_values_text, '')), 'C')
+      WHERE id = member_id_val;
+
+      RETURN COALESCE(NEW, OLD);
+    END
+    $$ LANGUAGE plpgsql;
+    """)
+
+    # Update existing search_vector values to include phone_number
+    execute("""
+    UPDATE members m
+    SET search_vector =
+      setweight(to_tsvector('simple', coalesce(m.first_name, '')), 'A') ||
+      setweight(to_tsvector('simple', coalesce(m.last_name, '')), 'A') ||
+      setweight(to_tsvector('simple', coalesce(m.email, '')), 'B') ||
+      setweight(to_tsvector('simple', coalesce(m.phone_number, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.join_date::text, '')), 'D') ||
+      setweight(to_tsvector('simple', coalesce(m.exit_date::text, '')), 'D') ||
+      setweight(to_tsvector('simple', coalesce(m.notes, '')), 'B') ||
+      setweight(to_tsvector('simple', coalesce(m.city, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.street, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.house_number::text, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(m.postal_code::text, '')), 'C') ||
+      setweight(to_tsvector('simple', coalesce(
+        (SELECT string_agg(
+          CASE
+            WHEN value ? '_union_value' THEN value->>'_union_value'
+            WHEN value ? 'value' THEN value->>'value'
+            ELSE ''
+          END,
+          ' '
+        )
+        FROM custom_field_values
+        WHERE member_id = m.id AND value IS NOT NULL),
+        ''
+      )), 'C')
+    """)
+  end
+end
diff --git a/priv/repo/seeds.exs b/priv/repo/seeds.exs
index fb102f4..4f99e5b 100644
--- a/priv/repo/seeds.exs
+++ b/priv/repo/seeds.exs
@@ -147,7 +147,6 @@ member_attrs_list = [
     last_name: "Müller",
     email: "hans.mueller@example.de",
     join_date: ~D[2023-01-15],
-    phone_number: "+49301234567",
     city: "München",
     street: "Hauptstraße",
     house_number: "42",
@@ -160,7 +159,6 @@ member_attrs_list = [
     last_name: "Schmidt",
     email: "greta.schmidt@example.de",
     join_date: ~D[2023-02-01],
-    phone_number: "+49309876543",
     city: "Hamburg",
     street: "Lindenstraße",
     house_number: "17",
@@ -174,7 +172,6 @@ member_attrs_list = [
     last_name: "Wagner",
     email: "friedrich.wagner@example.de",
     join_date: ~D[2022-11-10],
-    phone_number: "+49301122334",
     city: "Berlin",
     street: "Kastanienallee",
     house_number: "8",
@@ -186,7 +183,6 @@ member_attrs_list = [
     last_name: "Wagner",
     email: "marianne.wagner@example.de",
     join_date: ~D[2022-11-10],
-    phone_number: "+49301122334",
     city: "Berlin",
     street: "Kastanienallee",
     house_number: "8"
@@ -299,7 +295,6 @@ linked_members = [
     last_name: "Weber",
     email: "maria.weber@example.de",
     join_date: ~D[2023-03-15],
-    phone_number: "+49301357924",
     city: "Frankfurt",
     street: "Goetheplatz",
     house_number: "5",
@@ -313,7 +308,6 @@ linked_members = [
     last_name: "Klein",
     email: "thomas.klein@example.de",
     join_date: ~D[2023-04-01],
-    phone_number: "+49302468135",
     city: "Köln",
     street: "Rheinstraße",
     house_number: "23",
diff --git a/test/membership/member_test.exs b/test/membership/member_test.exs
index 1c4beb1..258d8be 100644
--- a/test/membership/member_test.exs
+++ b/test/membership/member_test.exs
@@ -7,7 +7,6 @@ defmodule Mv.Membership.MemberTest do
       first_name: "John",
       last_name: "Doe",
       email: "john@example.com",
-      phone_number: "+49123456789",
       join_date: ~D[2020-01-01],
       exit_date: nil,
       notes: "Test note",
@@ -17,16 +16,14 @@ defmodule Mv.Membership.MemberTest do
       postal_code: "12345"
     }
 
-    test "First name is required and must not be empty" do
-      attrs = Map.put(@valid_attrs, :first_name, "")
-      assert {:error, %Ash.Error.Invalid{errors: errors}} = Membership.create_member(attrs)
-      assert error_message(errors, :first_name) =~ "must be present"
+    test "First name is optional" do
+      attrs = Map.delete(@valid_attrs, :first_name)
+      assert {:ok, _member} = Membership.create_member(attrs)
     end
 
-    test "Last name is required and must not be empty" do
-      attrs = Map.put(@valid_attrs, :last_name, "")
-      assert {:error, %Ash.Error.Invalid{errors: errors}} = Membership.create_member(attrs)
-      assert error_message(errors, :last_name) =~ "must be present"
+    test "Last name is optional" do
+      attrs = Map.delete(@valid_attrs, :last_name)
+      assert {:ok, _member} = Membership.create_member(attrs)
     end
 
     test "Email is required" do
@@ -41,14 +38,6 @@ defmodule Mv.Membership.MemberTest do
       assert error_message(errors, :email) =~ "is not a valid email"
     end
 
-    test "Phone number is optional but must have a valid format if specified" do
-      attrs = Map.put(@valid_attrs, :phone_number, "abc")
-      assert {:error, %Ash.Error.Invalid{errors: errors}} = Membership.create_member(attrs)
-      assert error_message(errors, :phone_number) =~ "is not a valid phone number"
-      attrs2 = Map.delete(@valid_attrs, :phone_number)
-      assert {:ok, _member} = Membership.create_member(attrs2)
-    end
-
     test "Join date cannot be in the future" do
       attrs = Map.put(@valid_attrs, :join_date, Date.utc_today() |> Date.add(1))
 
diff --git a/test/mv_web/components/sort_header_component_test.exs b/test/mv_web/components/sort_header_component_test.exs
index e199635..6d23ab4 100644
--- a/test/mv_web/components/sort_header_component_test.exs
+++ b/test/mv_web/components/sort_header_component_test.exs
@@ -24,7 +24,6 @@ defmodule MvWeb.Components.SortHeaderComponentTest do
         :house_number,
         :postal_code,
         :city,
-        :phone_number,
         :join_date
       ]
 
@@ -101,7 +100,6 @@ defmodule MvWeb.Components.SortHeaderComponentTest do
       assert has_element?(view, "[data-testid='street'] .opacity-40")
       assert has_element?(view, "[data-testid='house_number'] .opacity-40")
       assert has_element?(view, "[data-testid='postal_code'] .opacity-40")
-      assert has_element?(view, "[data-testid='phone_number'] .opacity-40")
       assert has_element?(view, "[data-testid='join_date'] .opacity-40")
     end
 
diff --git a/test/mv_web/helpers/member_helpers_test.exs b/test/mv_web/helpers/member_helpers_test.exs
new file mode 100644
index 0000000..7a11235
--- /dev/null
+++ b/test/mv_web/helpers/member_helpers_test.exs
@@ -0,0 +1,141 @@
+defmodule MvWeb.Helpers.MemberHelpersTest do
+  @moduledoc """
+  Tests for the display_name/1 helper function in MemberHelpers.
+  """
+  use Mv.DataCase, async: true
+
+  alias Mv.Membership.Member
+  alias MvWeb.Helpers.MemberHelpers
+
+  describe "display_name/1" do
+    test "returns full name when both first_name and last_name are present" do
+      member = %Member{
+        first_name: "John",
+        last_name: "Doe",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John Doe"
+    end
+
+    test "returns email when both first_name and last_name are nil" do
+      member = %Member{
+        first_name: nil,
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "returns first_name only when last_name is nil" do
+      member = %Member{
+        first_name: "John",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John"
+    end
+
+    test "returns last_name only when first_name is nil" do
+      member = %Member{
+        first_name: nil,
+        last_name: "Doe",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "Doe"
+    end
+
+    test "returns email when first_name and last_name are empty strings" do
+      member = %Member{
+        first_name: "",
+        last_name: "",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "returns email when first_name and last_name are whitespace only" do
+      member = %Member{
+        first_name: "   ",
+        last_name: "  \t  ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "trims whitespace from name parts" do
+      member = %Member{
+        first_name: "  John  ",
+        last_name: "  Doe  ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John Doe"
+    end
+
+    test "handles one empty string and one nil" do
+      member = %Member{
+        first_name: "",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "handles one nil and one empty string" do
+      member = %Member{
+        first_name: nil,
+        last_name: "",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "handles one whitespace and one nil" do
+      member = %Member{
+        first_name: "   ",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "handles one valid name and one whitespace" do
+      member = %Member{
+        first_name: "John",
+        last_name: "   ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John"
+    end
+
+    test "handles member with only first_name containing whitespace" do
+      member = %Member{
+        first_name: "  John  ",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John"
+    end
+
+    test "handles member with only last_name containing whitespace" do
+      member = %Member{
+        first_name: nil,
+        last_name: "  Doe  ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "Doe"
+    end
+  end
+end
diff --git a/test/mv_web/member_live/index_display_name_test.exs b/test/mv_web/member_live/index_display_name_test.exs
new file mode 100644
index 0000000..7a11235
--- /dev/null
+++ b/test/mv_web/member_live/index_display_name_test.exs
@@ -0,0 +1,141 @@
+defmodule MvWeb.Helpers.MemberHelpersTest do
+  @moduledoc """
+  Tests for the display_name/1 helper function in MemberHelpers.
+  """
+  use Mv.DataCase, async: true
+
+  alias Mv.Membership.Member
+  alias MvWeb.Helpers.MemberHelpers
+
+  describe "display_name/1" do
+    test "returns full name when both first_name and last_name are present" do
+      member = %Member{
+        first_name: "John",
+        last_name: "Doe",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John Doe"
+    end
+
+    test "returns email when both first_name and last_name are nil" do
+      member = %Member{
+        first_name: nil,
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "returns first_name only when last_name is nil" do
+      member = %Member{
+        first_name: "John",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John"
+    end
+
+    test "returns last_name only when first_name is nil" do
+      member = %Member{
+        first_name: nil,
+        last_name: "Doe",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "Doe"
+    end
+
+    test "returns email when first_name and last_name are empty strings" do
+      member = %Member{
+        first_name: "",
+        last_name: "",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "returns email when first_name and last_name are whitespace only" do
+      member = %Member{
+        first_name: "   ",
+        last_name: "  \t  ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "trims whitespace from name parts" do
+      member = %Member{
+        first_name: "  John  ",
+        last_name: "  Doe  ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John Doe"
+    end
+
+    test "handles one empty string and one nil" do
+      member = %Member{
+        first_name: "",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "handles one nil and one empty string" do
+      member = %Member{
+        first_name: nil,
+        last_name: "",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "handles one whitespace and one nil" do
+      member = %Member{
+        first_name: "   ",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "john@example.com"
+    end
+
+    test "handles one valid name and one whitespace" do
+      member = %Member{
+        first_name: "John",
+        last_name: "   ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John"
+    end
+
+    test "handles member with only first_name containing whitespace" do
+      member = %Member{
+        first_name: "  John  ",
+        last_name: nil,
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "John"
+    end
+
+    test "handles member with only last_name containing whitespace" do
+      member = %Member{
+        first_name: nil,
+        last_name: "  Doe  ",
+        email: "john@example.com"
+      }
+
+      assert MemberHelpers.display_name(member) == "Doe"
+    end
+  end
+end
diff --git a/test/mv_web/member_live/index_member_fields_display_test.exs b/test/mv_web/member_live/index_member_fields_display_test.exs
index 6b4f50c..c6fd39f 100644
--- a/test/mv_web/member_live/index_member_fields_display_test.exs
+++ b/test/mv_web/member_live/index_member_fields_display_test.exs
@@ -16,7 +16,6 @@ defmodule MvWeb.MemberLive.IndexMemberFieldsDisplayTest do
         house_number: "123",
         postal_code: "12345",
         city: "Berlin",
-        phone_number: "+49123456789",
         join_date: ~D[2020-01-15]
       })
       |> Ash.create()
diff --git a/test/mv_web/member_live/index_test.exs b/test/mv_web/member_live/index_test.exs
index d4f5644..acca9bf 100644
--- a/test/mv_web/member_live/index_test.exs
+++ b/test/mv_web/member_live/index_test.exs
@@ -121,7 +121,6 @@ defmodule MvWeb.MemberLive.IndexTest do
         :house_number,
         :postal_code,
         :city,
-        :phone_number,
         :join_date
       ]