diff --git a/weed/worker/tasks/s3_lifecycle/handler.go b/weed/worker/tasks/s3_lifecycle/handler.go
index 3b4aad99f..caaf125b7 100644
--- a/weed/worker/tasks/s3_lifecycle/handler.go
+++ b/weed/worker/tasks/s3_lifecycle/handler.go
@@ -143,6 +143,15 @@ func (h *Handler) Descriptor() *plugin_pb.JobTypeDescriptor {
 			},
 		},
 		AdminRuntimeDefaults: &plugin_pb.AdminRuntimeDefaults{
+			// On by default: S3 lifecycle is a standard bucket feature
+			// (PutBucketLifecycleConfiguration is part of the S3 API),
+			// and a bucket with rules set but no worker running silently
+			// retains data past its declared expiration. Operators who
+			// want the worker off can still disable it in the admin UI;
+			// the default error is "data lingers" not "worker burns CPU
+			// on empty rule sets" (the worker fast-exits with no
+			// configured rules).
+			Enabled:                  true,
 			DetectionIntervalMinutes: 24 * 60, // daily
 			DetectionTimeoutSeconds:  60,
 			MaxJobsPerDetection:      1,
diff --git a/weed/worker/tasks/s3_lifecycle/handler_test.go b/weed/worker/tasks/s3_lifecycle/handler_test.go
index 1ea8331fc..5ed1beca4 100644
--- a/weed/worker/tasks/s3_lifecycle/handler_test.go
+++ b/weed/worker/tasks/s3_lifecycle/handler_test.go
@@ -348,6 +348,20 @@ func TestDescriptor_AdminRuntimeDefaultsDailyCadence(t *testing.T) {
 	assert.Equal(t, int32(1), d.AdminRuntimeDefaults.MaxJobsPerDetection)
 }
 
+func TestDescriptor_AdminRuntimeDefaultsEnabledByDefault(t *testing.T) {
+	// S3 lifecycle is a standard bucket feature — operators set
+	// PutBucketLifecycleConfiguration expecting it to actually fire.
+	// Default-off would silently retain data past declared expiration
+	// until an operator notices and flips it on. Document the choice
+	// here so a future change to disabled-by-default fails the test
+	// and surfaces a conscious revisit.
+	h := NewHandler(nil)
+	d := h.Descriptor()
+	require.NotNil(t, d.AdminRuntimeDefaults)
+	assert.True(t, d.AdminRuntimeDefaults.Enabled,
+		"s3_lifecycle defaults must enable the scheduler so configured rules fire without operator opt-in")
+}
+
 // ---------- Execute ----------
 
 // recordingExecSender captures Execute-side messages. The Execute path