I reflexively tuck my guitar picks in the strings whenever I stop playing, so I almost never lose them. (In fact, it seems I'm more likely to lose the new pack of picks I just bought than an individual one.) As a result, I wind up using the same pick until, well, this happens. Brand new pick on the left, exact same pick after a few months on the right.

I also always hold the pick the same way, with the lettering facing my thumb, so the tip of the pick wears down unevenly.