diff --git a/backend/src/main/java/com/petshop/backend/controller/MyPetController.java b/backend/src/main/java/com/petshop/backend/controller/MyPetController.java
index 18e8e914..5d4ad1ef 100644
--- a/backend/src/main/java/com/petshop/backend/controller/MyPetController.java
+++ b/backend/src/main/java/com/petshop/backend/controller/MyPetController.java
@@ -2,8 +2,6 @@ package com.petshop.backend.controller;
 
 import com.petshop.backend.dto.pet.MyPetRequest;
 import com.petshop.backend.dto.pet.MyPetResponse;
-import com.petshop.backend.entity.User;
-import com.petshop.backend.repository.UserRepository;
 import com.petshop.backend.service.PetService;
 import com.petshop.backend.util.AuthenticationHelper;
 import jakarta.validation.Valid;
@@ -22,7 +20,6 @@ import org.springframework.web.multipart.MultipartFile;
 
 import java.io.IOException;
 import java.util.List;
-import java.util.Map;
 
 @RestController
 @RequestMapping("/api/v1/my-pets")
@@ -30,47 +27,34 @@ import java.util.Map;
 public class MyPetController {
 
     private final PetService petService;
-    private final UserRepository userRepository;
 
-    public MyPetController(PetService petService, UserRepository userRepository) {
+    public MyPetController(PetService petService) {
         this.petService = petService;
-        this.userRepository = userRepository;
     }
 
     @GetMapping
     public ResponseEntity<List<MyPetResponse>> getMyPets(@RequestParam(required = false) String status) {
-        return ResponseEntity.ok(petService.getMyPets(currentUserId(), status));
+        return ResponseEntity.ok(petService.getMyPets(AuthenticationHelper.getAuthenticatedUserId(), status));
     }
 
     @PostMapping
     public ResponseEntity<MyPetResponse> createMyPet(@Valid @RequestBody MyPetRequest request) {
-        return ResponseEntity.ok(petService.createMyPet(currentUserId(), request));
+        return ResponseEntity.ok(petService.createMyPet(AuthenticationHelper.getAuthenticatedUserId(), request));
     }
 
     @PutMapping("/{id}")
     public ResponseEntity<MyPetResponse> updateMyPet(@PathVariable Long id, @Valid @RequestBody MyPetRequest request) {
-        return ResponseEntity.ok(petService.updateMyPet(currentUserId(), id, request));
+        return ResponseEntity.ok(petService.updateMyPet(AuthenticationHelper.getAuthenticatedUserId(), id, request));
     }
 
     @DeleteMapping("/{id}")
     public ResponseEntity<Void> deleteMyPet(@PathVariable Long id) {
-        petService.deleteMyPet(currentUserId(), id);
+        petService.deleteMyPet(AuthenticationHelper.getAuthenticatedUserId(), id);
         return ResponseEntity.noContent().build();
     }
 
     @PostMapping("/{id}/image")
-    public ResponseEntity<?> uploadMyPetImage(@PathVariable Long id, @RequestParam("image") MultipartFile image) {
-        try {
-            return ResponseEntity.ok(petService.uploadMyPetImage(currentUserId(), id, image));
-        } catch (IllegalArgumentException ex) {
-            return ResponseEntity.badRequest().body(Map.of("message", ex.getMessage()));
-        } catch (IOException ex) {
-            return ResponseEntity.badRequest().body(Map.of("message", "Failed to upload pet image: " + ex.getMessage()));
-        }
-    }
-
-    private Long currentUserId() {
-        User user = AuthenticationHelper.getAuthenticatedUser(userRepository);
-        return user.getId();
+    public ResponseEntity<MyPetResponse> uploadMyPetImage(@PathVariable Long id, @RequestParam("image") MultipartFile image) throws IOException {
+        return ResponseEntity.ok(petService.uploadMyPetImage(AuthenticationHelper.getAuthenticatedUserId(), id, image));
     }
 }
diff --git a/backend/src/main/java/com/petshop/backend/util/AuthenticationHelper.java b/backend/src/main/java/com/petshop/backend/util/AuthenticationHelper.java
index 4586ab2d..71f041ab 100644
--- a/backend/src/main/java/com/petshop/backend/util/AuthenticationHelper.java
+++ b/backend/src/main/java/com/petshop/backend/util/AuthenticationHelper.java
@@ -13,6 +13,12 @@ import org.springframework.stereotype.Component;
 @Component
 public class AuthenticationHelper {
 
+    private final UserRepository userRepository;
+
+    public AuthenticationHelper(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
     public static Authentication getAuthentication() {
         Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
         if (authentication == null || !authentication.isAuthenticated()) {
@@ -41,11 +47,19 @@ public class AuthenticationHelper {
         return getAuthenticatedPrincipal().getRole() == User.Role.CUSTOMER;
     }
 
-    public static Long getCustomerIdOrNull(UserRepository userRepository) {
+    public User getAuthenticatedUser() {
+        return getAuthenticatedUser(userRepository);
+    }
+
+    public Long getCustomerIdOrNull() {
         if (!isCustomer()) {
             return null;
         }
-        return getAuthenticatedUser(userRepository).getId();
+        return getAuthenticatedUser().getId();
+    }
+
+    public Long getEffectiveCustomerId(Long requestedCustomerId) {
+        return isCustomer() ? getAuthenticatedUser().getId() : requestedCustomerId;
     }
 
     public static User getAuthenticatedUser(UserRepository userRepository) {
diff --git a/backend/src/main/java/com/petshop/backend/util/StringUtils.java b/backend/src/main/java/com/petshop/backend/util/StringUtils.java
index 625c294d..fd795822 100644
--- a/backend/src/main/java/com/petshop/backend/util/StringUtils.java
+++ b/backend/src/main/java/com/petshop/backend/util/StringUtils.java
@@ -11,4 +11,20 @@ public final class StringUtils {
         String trimmed = value.trim();
         return trimmed.isEmpty() ? null : trimmed;
     }
+
+    public static String fullName(String firstName, String lastName) {
+        String first = trimToNull(firstName);
+        String last = trimToNull(lastName);
+        if (first == null) {
+            return last;
+        }
+        if (last == null) {
+            return first;
+        }
+        return first + " " + last;
+    }
+
+    public static String normalizePhone(String value) {
+        return trimToNull(PhoneUtils.normalize(trimToNull(value)));
+    }
 }