It's embarrassing to admit, but I have launched my boat without the plug - Twice (not recently). So I made a little reminder to prevent that from happenning again. Loosely connected a cable tie to one of my rear boat tie down straps (the metal hook part). Wrote "PLUG" on an extra Plano plastic box divider and drilled a small hole in it and attached a metal clip to it. When I remove the plug I attach the clip to the tie down on the rear strap. Since I have to remove the strap to launch the boat I'll be reminded that the plug is out. Keep it in the glove box when the plug is in.