How do you know if a hamsters teeth are over grown?

Question

my hamser is eating but not as much as he always does

Answer 1

You really bleed when he bites you....but seriously the top teeth seem to only grow to a certain length , The bottom teeth are the concern if they are longer than a tic-tac they need to be clipped a vet is your best option, go see one BTW it's cheap.

Answer 2

You will see them sticking out of his mouth, curving down toward his chin.  He may be getting old, and his appetite may be slowing down.