I used to, but I managed to stop a few years ago. I'm not entirely sure how I managed to stop. One summer I got reeaally into nail polish and ended up keeping my nails pretty long to take advantage of that and because the polish + finish made my nails a bit stronger, it was easier to take care of them. I'm too lazy for that now, but the good habits stuck and now I never have a problem with my nails getting too short! (If anything, I'm still not used to having to trim/file them down, so I often get to the point where they get ridiculously long and I start typoing all over the place because my nails are hitting keys on my keyboard that my fingers weren't intending to go near. 8D;;)
If you aren't a fan of obvious nail polish to try my way of quitting, there are clear polishes you can buy that don't show up but have a horrendous taste. They're not toxic or anything, they're specifically made to stop people from biting their nails because it removes the likelihood of you doing it without noticing. The moment a nail is in your mouth, you taste the horrible coat on it, and it's a reminder to stop. You still need a bit of willpower (in the right direction--or you'll power on right through the horrible taste to get at your nails :P) but it's a good slap on the wrist technique if you really want to put the effort in to quit. Once you've stopped, at least in my experience, you don't really start again.