Worn down? Wow, that's never happened to me. Usually the are too long, which is not a good thing. Thankfully, I've only had 2 breakages in the last 3 years, and even through all my pounding, hammering, chasing and sawing as a art student, none of them ever has been related to doing physical things. Just accidents, like you're driving one day and look down at your nail, and half of it is gone. Strangely, it's the middle fingernail that is the only one that ever breaks. Some people (including my parents) think I'm weird because I use a fine-toothed half-round bastard file from Metals class to shape me nails. I think I'd rather stick to a broken nail than Lee Press-On's!

--M