I thought about doing this when I started out, but never got around to it. I could see it being most useful for determining how many hours are on a piece of equipment, or how many cycles a battery has been through.

I just wouldn't want a written record of how many times I cartwheeled, dead-sticked, got my prop tangled in the tall grass, etc...

It's kind of like keeping track of how much money I have spent in this hobby. If I saw it in writing, I would probably cry.