diff --git a/app/Actions/Fortify/CreateNewUser.php b/app/Actions/Fortify/CreateNewUser.php
index 3c7c00c..d7e1a36 100644
--- a/app/Actions/Fortify/CreateNewUser.php
+++ b/app/Actions/Fortify/CreateNewUser.php
@@ -3,14 +3,14 @@
 namespace App\Actions\Fortify;
 
 use App\Concerns\PasswordValidationRules;
-use App\Concerns\ProfileValidationRules;
 use App\Models\User;
 use Illuminate\Support\Facades\Validator;
+use Illuminate\Validation\Rule;
 use Laravel\Fortify\Contracts\CreatesNewUsers;
 
 class CreateNewUser implements CreatesNewUsers
 {
-    use PasswordValidationRules, ProfileValidationRules;
+    use PasswordValidationRules;
 
     /**
      * Validate and create a newly registered user.
@@ -20,7 +20,8 @@ class CreateNewUser implements CreatesNewUsers
     public function create(array $input): User
     {
         Validator::make($input, [
-            ...$this->profileRules(),
+            'name' => ['required', 'string', 'max:255'],
+            'email' => ['required', 'string', 'email', 'max:255', Rule::unique(User::class)],
             'password' => $this->passwordRules(),
         ])->validate();
 
diff --git a/app/Concerns/PasswordValidationRules.php b/app/Concerns/PasswordValidationRules.php
index e858302..1d6c887 100644
--- a/app/Concerns/PasswordValidationRules.php
+++ b/app/Concerns/PasswordValidationRules.php
@@ -16,14 +16,4 @@ trait PasswordValidationRules
     {
         return ['required', 'string', Password::default(), 'confirmed'];
     }
-
-    /**
-     * Get the validation rules used to validate the current password.
-     *
-     * @return array<int, Rule|array<mixed>|string>
-     */
-    protected function currentPasswordRules(): array
-    {
-        return ['required', 'string', 'current_password'];
-    }
 }
diff --git a/app/Concerns/ProfileValidationRules.php b/app/Concerns/ProfileValidationRules.php
deleted file mode 100644
index 46e19ba..0000000
--- a/app/Concerns/ProfileValidationRules.php
+++ /dev/null
@@ -1,50 +0,0 @@
-<?php
-
-namespace App\Concerns;
-
-use App\Models\User;
-use Illuminate\Validation\Rule;
-
-trait ProfileValidationRules
-{
-    /**
-     * Get the validation rules used to validate user profiles.
-     *
-     * @return array<string, array<int, \Illuminate\Contracts\Validation\Rule|array<mixed>|string>>
-     */
-    protected function profileRules(?int $userId = null): array
-    {
-        return [
-            'name' => $this->nameRules(),
-            'email' => $this->emailRules($userId),
-        ];
-    }
-
-    /**
-     * Get the validation rules used to validate user names.
-     *
-     * @return array<int, \Illuminate\Contracts\Validation\Rule|array<mixed>|string>
-     */
-    protected function nameRules(): array
-    {
-        return ['required', 'string', 'max:255'];
-    }
-
-    /**
-     * Get the validation rules used to validate user emails.
-     *
-     * @return array<int, \Illuminate\Contracts\Validation\Rule|array<mixed>|string>
-     */
-    protected function emailRules(?int $userId = null): array
-    {
-        return [
-            'required',
-            'string',
-            'email',
-            'max:255',
-            $userId === null
-                ? Rule::unique(User::class)
-                : Rule::unique(User::class)->ignore($userId),
-        ];
-    }
-}
diff --git a/app/Services/Prediction/Signals/DayOfWeekSignal.php b/app/Services/Prediction/Signals/DayOfWeekSignal.php
index 8149c51..f3b464e 100644
--- a/app/Services/Prediction/Signals/DayOfWeekSignal.php
+++ b/app/Services/Prediction/Signals/DayOfWeekSignal.php
@@ -10,10 +10,7 @@ final class DayOfWeekSignal extends AbstractSignal
 
     public function compute(SignalContext $context): array
     {
-        $isSqlite = DB::connection()->getDriverName() === 'sqlite';
-        $dowExpr = $isSqlite
-            ? "(CAST(strftime('%w', price_effective_at) AS INTEGER) + 1)"
-            : 'DAYOFWEEK(price_effective_at)';
+        $dowExpr = DbDialect::dayOfWeekExpr('price_effective_at');
 
         $rows = DB::table('station_prices')
             ->where('fuel_type', $context->fuelType->value)
diff --git a/app/Services/Prediction/Signals/DbDialect.php b/app/Services/Prediction/Signals/DbDialect.php
new file mode 100644
index 0000000..40cd53c
--- /dev/null
+++ b/app/Services/Prediction/Signals/DbDialect.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace App\Services\Prediction\Signals;
+
+use Illuminate\Support\Facades\DB;
+
+/**
+ * SQL dialect helpers for the small set of MySQL/SQLite differences the
+ * signal classes care about. Centralises the isSqlite ternaries that were
+ * duplicated across DayOfWeekSignal and StickinessSignal.
+ */
+final class DbDialect
+{
+    private static function isSqlite(): bool
+    {
+        return DB::connection()->getDriverName() === 'sqlite';
+    }
+
+    /**
+     * Day-of-week expression returning 1=Sun..7=Sat (MySQL DAYOFWEEK convention).
+     * Targets a column on the queried table.
+     */
+    public static function dayOfWeekExpr(string $column): string
+    {
+        return self::isSqlite()
+            ? "(CAST(strftime('%w', {$column}) AS INTEGER) + 1)"
+            : "DAYOFWEEK({$column})";
+    }
+
+    /**
+     * Whole-day difference between MAX and MIN of a datetime column, suitable
+     * for use in an aggregate selectRaw.
+     */
+    public static function maxMinDayDiffExpr(string $column): string
+    {
+        return self::isSqlite()
+            ? "CAST((julianday(MAX({$column})) - julianday(MIN({$column}))) AS INTEGER)"
+            : "DATEDIFF(MAX({$column}), MIN({$column}))";
+    }
+}
diff --git a/app/Services/Prediction/Signals/StickinessSignal.php b/app/Services/Prediction/Signals/StickinessSignal.php
index 89af42a..e463d84 100644
--- a/app/Services/Prediction/Signals/StickinessSignal.php
+++ b/app/Services/Prediction/Signals/StickinessSignal.php
@@ -8,10 +8,7 @@ final class StickinessSignal extends AbstractSignal
 {
     public function compute(SignalContext $context): array
     {
-        $isSqlite = DB::connection()->getDriverName() === 'sqlite';
-        $diffExpr = $isSqlite
-            ? 'CAST((julianday(MAX(price_effective_at)) - julianday(MIN(price_effective_at))) AS INTEGER)'
-            : 'DATEDIFF(MAX(price_effective_at), MIN(price_effective_at))';
+        $diffExpr = DbDialect::maxMinDayDiffExpr('price_effective_at');
 
         $rows = DB::table('station_prices')
             ->where('fuel_type', $context->fuelType->value)