a reminder should arrive and then leave

A reminder should appear when it can help. Not too early, not again and again, and not with the urgency of something more important than it is.

Once it has brought something back to mind, its work is done. It should be easy to dismiss, ignore, or act on without leaving behind another badge to clear.

A good reminder does not try to keep our attention. It briefly returns attention to something we chose, then quietly steps away.