diff --git a/src/main.rs b/src/main.rs
index 57c2722..879468a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -104,7 +104,14 @@ impl Resources {
                             .filter(schema::calendars::dsl::id.eq(id.clone()))
                             .set(schema::calendars::dsl::last_fetch.eq(Utc::now().naive_utc()))
                             .execute(&db)?;
-                        Ok((cal.etag.clone(), cal.last_modified.clone()))
+                        let result =
+                            // Use ETag/Last-Modified only if URL hasn't changed
+                            if cal.url == cal_opts.url {
+                                (cal.etag.clone(), cal.last_modified.clone())
+                            } else {
+                                (None, None)
+                            };
+                        Ok(result)
                     }
                 }
             })?;