i bite my nails too. It's a nervous habit.. like if i dont know what to do with my hands, i just bite my nails. it gives me somethign to concentrate on.. idk. When i got braces i stopped biting my nails entirely because it hurt too bad to even chew food let alone bite a nail. But now i dont have braces anymore, And i'm back to it. I find that wearing nail polish works for me because it tastes gross... or i'll want my nails to look pretty and so i just leave them alone. But I think they actually have gross tasting stuff you can put on your nails to stop from biting them.