diff --git a/src/apps/billboard/tests/integrated/test_views.py b/src/apps/billboard/tests/integrated/test_views.py
index b5ed60e..0d2938d 100644
--- a/src/apps/billboard/tests/integrated/test_views.py
+++ b/src/apps/billboard/tests/integrated/test_views.py
@@ -433,3 +433,51 @@ class SaveScrollPositionTest(TestCase):
             {"position": 100},
         )
         self.assertEqual(response.status_code, 302)
+
+
+class PostLineRelativeTimestampTest(TestCase):
+    """post.html mirrors scroll.html's bucketed `relative_ts` time rendering:
+    same-day Lines show a time; older ones collapse to weekday / month-day /
+    month-day-year. Bypasses `auto_now_add` with a queryset .update() so the
+    test can backdate Lines."""
+
+    def setUp(self):
+        self.owner = User.objects.create(email="owner@post-ts.io", username="owner")
+        self.client.force_login(self.owner)
+        from apps.billboard.models import Line, Post
+        self.Line = Line
+        self.post = Post.objects.create(owner=self.owner, title="Stamp")
+
+    def _backdate(self, line, **delta):
+        from apps.billboard.models import Line
+        Line.objects.filter(pk=line.pk).update(
+            created_at=timezone.now() - timezone.timedelta(**delta)
+        )
+
+    def test_recent_line_renders_clock_time(self):
+        self.Line.objects.create(post=self.post, text="now", author=self.owner)
+        response = self.client.get(reverse("billboard:view_post", args=[self.post.id]))
+        self.assertRegex(
+            response.content.decode(),
+            r'class="post-line-time"[^>]*>\s*\d+:\d{2}\s*[ap]\.m\.\s*<',
+        )
+
+    def test_two_day_old_line_renders_weekday(self):
+        line = self.Line.objects.create(post=self.post, text="old", author=self.owner)
+        self._backdate(line, days=2)
+        response = self.client.get(reverse("billboard:view_post", args=[self.post.id]))
+        import re
+        m = re.search(
+            r'class="post-line-time"[^>]*>\s*(\w+)\s*<', response.content.decode()
+        )
+        self.assertIsNotNone(m, "no .post-line-time cell rendered")
+        self.assertIn(m.group(1), {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"})
+
+    def test_thirty_day_old_line_renders_day_month(self):
+        line = self.Line.objects.create(post=self.post, text="oldr", author=self.owner)
+        self._backdate(line, days=30)
+        response = self.client.get(reverse("billboard:view_post", args=[self.post.id]))
+        self.assertRegex(
+            response.content.decode(),
+            r'class="post-line-time"[^>]*>\s*\d{2}\s\w{3}\s*<',
+        )
diff --git a/src/templates/apps/billboard/post.html b/src/templates/apps/billboard/post.html
index abccf5f..0c42722 100644
--- a/src/templates/apps/billboard/post.html
+++ b/src/templates/apps/billboard/post.html
@@ -42,7 +42,7 @@
             <li class="post-line {% if line.author.username == 'adman' %}post-line--system{% endif %}">
                 <span class="post-line-author">{{ line.author|at_handle }}</span>
                 <span class="post-line-text">{# adman-authored Lines (note unlock + share invite system prose) carry an `<a class="note-ref">` anchor that needs to render as HTML. User-typed Lines stay escaped. #}{% if line.author.username == 'adman' %}{{ line.text|safe }}{% else %}{{ line.text }}{% endif %}</span>
-                <time class="post-line-time" datetime="{{ line.created_at|date:'c' }}">{{ line.created_at|date:'g:i A' }}</time>
+                <time class="post-line-time" datetime="{{ line.created_at|date:'c' }}">{{ line.created_at|relative_ts }}</time>
             </li>
         {% endfor %}
         <li class="post-line-buffer" aria-hidden="true"></li>