diff --git a/hc/front/tests/test_add_email.py b/hc/front/tests/test_add_email.py
index 05e35f02..65be61d9 100644
--- a/hc/front/tests/test_add_email.py
+++ b/hc/front/tests/test_add_email.py
@@ -3,14 +3,15 @@ import json
 from django.core import mail
 from django.test.utils import override_settings
 
-from hc.api.models import Channel
+from hc.api.models import Channel, Check
 from hc.test import BaseTestCase
 
 
 class AddEmailTestCase(BaseTestCase):
     def setUp(self):
         super().setUp()
-        self.url = "/projects/%s/add_email/" % self.project.code
+        self.check = Check.objects.create(project=self.project)
+        self.url = f"/projects/{self.project.code}/add_email/"
 
     def test_instructions_work(self):
         self.client.login(username="alice@example.org", password="password")
@@ -41,6 +42,9 @@ class AddEmailTestCase(BaseTestCase):
         # Make sure we're sending to an email address, not a JSON string:
         self.assertEqual(email.to[0], "dan@example.org")
 
+        # Make sure it calls assign_all_checks
+        self.assertEqual(c.checks.count(), 1)
+
     def test_team_access_works(self):
         form = {"value": "bob@example.org", "down": "true", "up": "true"}
 
diff --git a/hc/front/tests/test_add_webhook.py b/hc/front/tests/test_add_webhook.py
index 53c5bef6..fdf58404 100644
--- a/hc/front/tests/test_add_webhook.py
+++ b/hc/front/tests/test_add_webhook.py
@@ -1,12 +1,13 @@
 from django.test.utils import override_settings
-from hc.api.models import Channel
+from hc.api.models import Channel, Check
 from hc.test import BaseTestCase
 
 
 class AddWebhookTestCase(BaseTestCase):
     def setUp(self):
         super().setUp()
-        self.url = "/projects/%s/add_webhook/" % self.project.code
+        self.check = Check.objects.create(project=self.project)
+        self.url = f"/projects/{self.project.code}/add_webhook/"
 
     def test_instructions_work(self):
         self.client.login(username="alice@example.org", password="password")
@@ -29,6 +30,9 @@ class AddWebhookTestCase(BaseTestCase):
         c = Channel.objects.get()
         self.assertEqual(c.name, "Call foo.com")
 
+        # Make sure it calls assign_all_checks
+        self.assertEqual(c.checks.count(), 1)
+
     def test_it_adds_two_webhook_urls_and_redirects(self):
         form = {
             "method_down": "GET",
diff --git a/hc/front/tests/test_edit_email.py b/hc/front/tests/test_edit_email.py
index d17401b1..5424c999 100644
--- a/hc/front/tests/test_edit_email.py
+++ b/hc/front/tests/test_edit_email.py
@@ -3,7 +3,7 @@ import json
 from django.core import mail
 from django.test.utils import override_settings
 
-from hc.api.models import Channel
+from hc.api.models import Channel, Check
 from hc.test import BaseTestCase
 
 
@@ -11,6 +11,8 @@ class EditEmailTestCase(BaseTestCase):
     def setUp(self):
         super().setUp()
 
+        self.check = Check.objects.create(project=self.project)
+
         self.channel = Channel(project=self.project, kind="email")
         self.channel.value = json.dumps(
             {"value": "alerts@example.org", "up": True, "down": True}
@@ -18,7 +20,7 @@ class EditEmailTestCase(BaseTestCase):
         self.channel.email_verified = True
         self.channel.save()
 
-        self.url = "/integrations/%s/edit/" % self.channel.code
+        self.url = f"/integrations/{self.channel.code}/edit/"
 
     def test_it_shows_form(self):
         self.client.login(username="alice@example.org", password="password")
@@ -44,6 +46,9 @@ class EditEmailTestCase(BaseTestCase):
         self.assertTrue(email.subject.startswith("Verify email address on"))
         self.assertEqual(email.to[0], "new@example.org")
 
+        # Make sure it does not call assign_all_checks
+        self.assertFalse(self.channel.checks.exists())
+
     def test_it_skips_verification_if_email_unchanged(self):
         form = {"value": "alerts@example.org", "down": "false", "up": "true"}
 
diff --git a/hc/front/tests/test_edit_webhook.py b/hc/front/tests/test_edit_webhook.py
index 1c71e7a3..34907d21 100644
--- a/hc/front/tests/test_edit_webhook.py
+++ b/hc/front/tests/test_edit_webhook.py
@@ -1,6 +1,6 @@
 import json
 
-from hc.api.models import Channel
+from hc.api.models import Channel, Check
 from hc.test import BaseTestCase
 
 
@@ -8,6 +8,8 @@ class EditWebhookTestCase(BaseTestCase):
     def setUp(self):
         super().setUp()
 
+        self.check = Check.objects.create(project=self.project)
+
         definition = {
             "method_down": "GET",
             "url_down": "http://example.org/down",
@@ -24,7 +26,7 @@ class EditWebhookTestCase(BaseTestCase):
         self.channel.value = json.dumps(definition)
         self.channel.save()
 
-        self.url = "/integrations/%s/edit/" % self.channel.code
+        self.url = f"/integrations/{self.channel.code}/edit/"
 
     def test_it_shows_form(self):
         self.client.login(username="alice@example.org", password="password")
@@ -74,6 +76,9 @@ class EditWebhookTestCase(BaseTestCase):
         self.assertEqual(up_spec["body"], "going up")
         self.assertEqual(up_spec["headers"], {"Content-Type": "text/plain"})
 
+        # Make sure it does not call assign_all_checks
+        self.assertFalse(self.channel.checks.exists())
+
     def test_it_requires_kind_webhook(self):
         self.channel.kind = "sms"
         self.channel.value = "foo@example.org"
diff --git a/hc/front/views.py b/hc/front/views.py
index f1fe1720..25878d42 100644
--- a/hc/front/views.py
+++ b/hc/front/views.py
@@ -1031,7 +1031,9 @@ def webhook_form(request, channel=None, code=None):
             channel.value = form.get_value()
             channel.save()
 
-            channel.assign_all_checks()
+            if is_new:
+                channel.assign_all_checks()
+
             return redirect("hc-channels", channel.project.code)
 
     elif is_new: