diff --git a/backend/dropbox/dropbox.go b/backend/dropbox/dropbox.go
index 446f475f8..000bfd5e4 100644
--- a/backend/dropbox/dropbox.go
+++ b/backend/dropbox/dropbox.go
@@ -1370,10 +1370,12 @@ func (f *Fs) changeNotifyRunner(ctx context.Context, notifyFunc func(string, fs.
 
 	if timeout < 30 {
 		timeout = 30
+		fs.Debugf(f, "Increasing poll interval to minimum 30s")
 	}
 
 	if timeout > 480 {
 		timeout = 480
+		fs.Debugf(f, "Decreasing poll interval to maximum 480s")
 	}
 
 	err = f.pacer.Call(func() (bool, error) {