When should I rehair my bow?

1. Most of the hair is broken from playing
2. The hair has been eaten by Carpet Beetle Larvae
3. The hair is very old and britle
4. Putting rosin on the hair and it still seems slick
5. Oil or polish has gotten on the hair

How to make your hair last longer.

1. I have noticed that a lot of customers break hair in the middle of the stick. Sometimes this happens when you are playing too hard for how tight or strong the stick is. Basically you are grinding the hair between the stick and the string.
2. You are playing too hard on one side of the stick. Try to have the bow just a little flatter so the force of playing is across most of the hair instead of just one side.