diff --git a/content/tests.py b/content/tests.py
index 88b30e1..5094a7a 100644
--- a/content/tests.py
+++ b/content/tests.py
@@ -1,12 +1,15 @@
+from datetime import timedelta
 from unittest.mock import patch
 
 from django.test import TestCase
+from django.utils import timezone
 from rest_framework.test import APIClient
 from rest_framework.throttling import ScopedRateThrottle
 
 from accounts.authentication import issue_access_token
 from accounts.models import User
 from progress.models import UserHearts, UserStats
+from subscription.models import Plan, Subscription
 
 from .models import Choice, Grade, Lesson, Node, NodeProgress, Question, Unit, UserAnswer, UserLessonCompletion
 
@@ -636,6 +639,63 @@ class GradesListCacheTests(TestCase):
         self.assertEqual(len(r3.data['grades']), 2)
 
 
+class UnlimitedHeartsSubscriptionTests(TestCase):
+    """رگرسیون: هر مشترکِ فعال (فارغ از پلن) نباید با جوابِ غلط هارت از دست بده."""
+
+    def setUp(self):
+        self.client = APIClient()
+        self.user = User.objects.create(device_id='dev-unlimited-hearts', is_guest=True, name='')
+        self.token = issue_access_token(self.user.id)
+
+        grade = Grade.objects.create(title='پایه اول', icon='icon', color='#fff')
+        unit = Unit.objects.create(grade=grade, title='فصل ۱', order=1)
+        node = Node.objects.create(unit=unit, title='گره ۱', order=1)
+        lesson = Lesson.objects.create(node=node, title='درس ۱', intro_text='...')
+        self.question = Question.objects.create(lesson=lesson, type='multiple_choice', prompt='سوال ۱')
+        Choice.objects.create(question=self.question, value='درست', is_correct=True)
+        self.wrong_choice = Choice.objects.create(question=self.question, value='غلط', is_correct=False)
+
+    def _answer_wrong(self):
+        return self.client.post(
+            f'/api/questions/{self.question.id}/answer',
+            {'selectedOptionId': str(self.wrong_choice.id)},
+            format='json',
+            HTTP_AUTHORIZATION=f'Bearer {self.token}',
+        )
+
+    def test_wrong_answer_costs_a_heart_without_subscription(self):
+        UserHearts.objects.create(user_id=self.user.id, current_hearts=5, max_hearts=5)
+
+        response = self._answer_wrong()
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.data['heartsRemaining'], 4)
+
+    def test_wrong_answer_does_not_cost_a_heart_with_active_subscription(self):
+        UserHearts.objects.create(user_id=self.user.id, current_hearts=5, max_hearts=5)
+        plan = Plan.objects.create(title='ماهانه', price=100000)
+        Subscription.objects.create(
+            user_id=self.user.id, plan=plan, status='active',
+            expires_at=timezone.now() + timedelta(days=30),
+        )
+
+        response = self._answer_wrong()
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.data['heartsRemaining'], 5)
+        self.assertEqual(UserHearts.objects.get(user_id=self.user.id).current_hearts, 5)
+
+    def test_expired_subscription_still_costs_a_heart(self):
+        UserHearts.objects.create(user_id=self.user.id, current_hearts=5, max_hearts=5)
+        plan = Plan.objects.create(title='ماهانه', price=100000)
+        Subscription.objects.create(
+            user_id=self.user.id, plan=plan, status='active',
+            expires_at=timezone.now() - timedelta(days=1),
+        )
+
+        response = self._answer_wrong()
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.data['heartsRemaining'], 4)
+
+
 class ReadThrottleTests(TestCase):
     def setUp(self):
         _django_cache.clear()
diff --git a/content/views.py b/content/views.py
index 675ce70..fa227a0 100644
--- a/content/views.py
+++ b/content/views.py
@@ -11,6 +11,7 @@ from rest_framework.throttling import ScopedRateThrottle
 from rest_framework.views import APIView
 
 from progress.models import UserHearts, UserStats
+from subscription.services import has_unlimited_hearts
 
 from .models import Choice, Grade, Lesson, NodeProgress, Question, UserAnswer, UserLessonCompletion
 from .serializers import (
@@ -308,9 +309,10 @@ class QuestionAnswerView(APIView):
                 if not choice.is_correct:
                     UserHearts.objects.get_or_create(user_id=user_id)
                     hearts = UserHearts.objects.select_for_update().get(user_id=user_id)
-                    if hearts.current_hearts > 0:
-                        hearts.current_hearts -= 1
-                        hearts.save(update_fields=['current_hearts'])
+                    hearts.apply_regen()
+                    if not has_unlimited_hearts(user_id):
+                        hearts.lose_heart()
+                    hearts.save(update_fields=['current_hearts', 'next_refill_at'])
                     hearts_remaining = hearts.current_hearts
                 else:
                     hearts = UserHearts.objects.filter(user_id=user_id).first()
diff --git a/progress/models.py b/progress/models.py
index b678f74..6b8482d 100644
--- a/progress/models.py
+++ b/progress/models.py
@@ -1,4 +1,9 @@
+from datetime import timedelta
+
 from django.db import models
+from django.utils import timezone
+
+HEART_REFILL_INTERVAL = timedelta(hours=24)
 
 
 class UserStats(models.Model):
@@ -54,3 +59,36 @@ class UserHearts(models.Model):
 
     def __str__(self):
         return f"hearts-user{self.user_id}"
+
+    def apply_regen(self):
+        """اگه از next_refill_at گذشته باشه، هارت(های) گذشته رو پر می‌کنه (چندتا هم
+        اگه کاربر چند بازه‌ی HEART_REFILL_INTERVAL غایب بوده باشه). True یعنی
+        state عوض شده و باید save بشه."""
+        if self.current_hearts >= self.max_hearts:
+            if self.next_refill_at is not None:
+                self.next_refill_at = None
+                return True
+            return False
+
+        now = timezone.now()
+        if self.next_refill_at is None:
+            self.next_refill_at = now + HEART_REFILL_INTERVAL
+            return True
+        if now < self.next_refill_at:
+            return False
+
+        elapsed_intervals = 1 + (now - self.next_refill_at) // HEART_REFILL_INTERVAL
+        gained = min(elapsed_intervals, self.max_hearts - self.current_hearts)
+        self.current_hearts += gained
+        if self.current_hearts >= self.max_hearts:
+            self.next_refill_at = None
+        else:
+            self.next_refill_at += elapsed_intervals * HEART_REFILL_INTERVAL
+        return True
+
+    def lose_heart(self):
+        """یک هارت کم می‌کنه؛ اگه تایمرِ refill از قبل در حال شمارش نیست، از الان شروعش می‌کنه."""
+        if self.current_hearts > 0:
+            self.current_hearts -= 1
+        if self.next_refill_at is None and self.current_hearts < self.max_hearts:
+            self.next_refill_at = timezone.now() + HEART_REFILL_INTERVAL
diff --git a/progress/serializers.py b/progress/serializers.py
index 4abe634..08fcd30 100644
--- a/progress/serializers.py
+++ b/progress/serializers.py
@@ -39,3 +39,4 @@ class UserHeartsResponseSerializer(serializers.Serializer):
     currentHearts = serializers.IntegerField()
     maxHearts = serializers.IntegerField()
     nextRefillAt = serializers.DateTimeField(allow_null=True)
+    isUnlimited = serializers.BooleanField()
diff --git a/progress/tests.py b/progress/tests.py
index a39b155..07a264b 100644
--- a/progress/tests.py
+++ b/progress/tests.py
@@ -1 +1,62 @@
-# Create your tests here.
+from datetime import timedelta
+
+from django.test import TestCase
+from django.utils import timezone
+from rest_framework.test import APIClient
+
+from accounts.authentication import issue_access_token
+from accounts.models import User
+
+from .models import HEART_REFILL_INTERVAL, UserHearts
+
+
+class UserHeartsRegenTests(TestCase):
+    """رگرسیون: قبلاً next_refill_at هیچ‌وقت واقعاً چک نمی‌شد و هارتِ ازدست‌رفته
+    برای همیشه صفر می‌موند."""
+
+    def setUp(self):
+        self.client = APIClient()
+        self.user = User.objects.create(device_id='dev-hearts-regen', is_guest=True, name='')
+        self.token = issue_access_token(self.user.id)
+
+    def _get_hearts(self):
+        return self.client.get('/api/user/hearts', HTTP_AUTHORIZATION=f'Bearer {self.token}')
+
+    def test_no_refill_before_interval_elapses(self):
+        hearts = UserHearts.objects.create(user_id=self.user.id, current_hearts=3, max_hearts=5)
+        hearts.lose_heart()  # شبیه‌سازیِ از دست دادنِ یک هارتِ دیگه؛ تایمر رو ست می‌کنه
+        hearts.save()
+
+        response = self._get_hearts()
+        self.assertEqual(response.data['currentHearts'], 2)
+        self.assertIsNotNone(response.data['nextRefillAt'])
+
+    def test_refill_after_interval_elapses(self):
+        hearts = UserHearts.objects.create(
+            user_id=self.user.id, current_hearts=3, max_hearts=5,
+            next_refill_at=timezone.now() - timedelta(seconds=1),
+        )
+
+        response = self._get_hearts()
+        self.assertEqual(response.data['currentHearts'], 4)
+
+        hearts.refresh_from_db()
+        self.assertEqual(hearts.current_hearts, 4)
+        self.assertIsNotNone(hearts.next_refill_at)  # هنوز به max نرسیده، تایمرِ بعدی ست شده
+
+    def test_refill_catches_up_multiple_missed_intervals(self):
+        UserHearts.objects.create(
+            user_id=self.user.id, current_hearts=1, max_hearts=5,
+            next_refill_at=timezone.now() - 3 * HEART_REFILL_INTERVAL,
+        )
+
+        response = self._get_hearts()
+        self.assertEqual(response.data['currentHearts'], 5)
+        self.assertIsNone(response.data['nextRefillAt'])  # به max رسیده، تایمر خاموش می‌شه
+
+    def test_full_hearts_have_no_refill_timer(self):
+        UserHearts.objects.create(user_id=self.user.id, current_hearts=5, max_hearts=5)
+
+        response = self._get_hearts()
+        self.assertEqual(response.data['currentHearts'], 5)
+        self.assertIsNone(response.data['nextRefillAt'])
diff --git a/progress/views.py b/progress/views.py
index 9851bfb..084a43a 100644
--- a/progress/views.py
+++ b/progress/views.py
@@ -122,11 +122,18 @@ class UserHeartsView(APIView):
 
     @extend_schema(responses=UserHeartsResponseSerializer, tags=['Progress & Gamification (progress)'])
     def get(self, request):
+        from subscription.services import has_unlimited_hearts
+
         user = request.user
         hearts, _ = UserHearts.objects.get_or_create(user_id=user.id)
+        if hearts.apply_regen():
+            hearts.save(update_fields=['current_hearts', 'next_refill_at'])
+
+        unlimited = has_unlimited_hearts(user.id)
         data = {
-            'currentHearts': hearts.current_hearts,
+            'currentHearts': hearts.max_hearts if unlimited else hearts.current_hearts,
             'maxHearts': hearts.max_hearts,
-            'nextRefillAt': hearts.next_refill_at,
+            'nextRefillAt': None if unlimited else hearts.next_refill_at,
+            'isUnlimited': unlimited,
         }
         return Response(UserHeartsResponseSerializer(data).data)
diff --git a/subscription/services.py b/subscription/services.py
index 12d9d54..b24d99a 100644
--- a/subscription/services.py
+++ b/subscription/services.py
@@ -1,4 +1,4 @@
-from django.db import transaction
+from django.db import models, transaction
 from django.utils import timezone
 
 from statuslog.signals import status_changed
@@ -6,6 +6,19 @@ from statuslog.signals import status_changed
 from .models import Subscription
 
 
+def has_unlimited_hearts(user_id: int) -> bool:
+    """آیا کاربر اشتراکِ فعال داره (progress.UserHearts از این استفاده می‌کنه تا
+    هارت کم نکنه). فعلاً هر اشتراکِ فعال، فارغ از پلن/مدت، این پرک رو می‌ده —
+    وقتی محصول پلن‌های متفاوت با پرکِ متفاوت خواست، این تابع دقیق‌تر می‌شه.
+    expires_at=None یعنی اشتراکِ نامحدود (grant_free_subscription با duration_days=None)."""
+    now = timezone.now()
+    return Subscription.objects.filter(
+        user_id=user_id, status='active',
+    ).filter(
+        models.Q(expires_at__isnull=True) | models.Q(expires_at__gt=now)
+    ).exists()
+
+
 def activate_subscription(subscription_id: int):
     """
     بعد از تایید پرداخت (payment webhook) صدا زده می‌شود؛ اشتراک را active