It's Sunday, which often means household projects around here. I was just cleaning my keyboard and trying to remember how long I've had it. I think it's been 2-3 years, but I can't remember exactly. A while, but not ridiculously long, ya know? Anyway, there are seven keys where I have actually worn off part of the letter (all of the letter A, actually). I'm thinking it's entirely possible I type a lot.
The keyboard - now thoroughly cleaned - looks very nice now, despite missing letters. Those that don't touch-type probably wouldn't want to use it.
Of course, the concern here would be that the keyboard would actually have to be replaced sometime, which is frightening. I'm not fond of change anyway, and to have a whole different keyboard would not make me a happy camper.