Duane solved a problem I never even realized was a problem, but is:
I'm lousy at keeping the batteries in the kids' toys up to date. Not so much the small, often-played-with toys where my 4 year-old can say "Daddy this needs new batteries," but more for the baby's bassinet and other toys that vibrate, which go through batteries like crazy but you can't just sit at the kitchen table and fix, you have to flip it over and take it apart. "I don't know if I have batteries for that," I'll tell myself, since you never know until you open it whether you'll find C, D or the occasional AA. Now I just put a piece of tape on the battery cover and write down what size batteries are in there. Now I don't have to bother taking it apart just to realize that I need to go find 4 D's.
[This advice doesn't apply to those toys whose batteries you WANT to run out so you don't have to listen to their infernal noise. Before my son became wise to the ways of electronics, I had been known to say, "Sorry, sweetie…it's broken." — Ed.]