Change cams, change modules, reserve strings, change limbs, change axles and bushings, pretty much anything you want to do to a bow a press is a must. LifeNRA is right; the bowmaster press is a must, this little dude is the stuff. Take that little booger with you anywhere and work on a bow. JMO its more practical than a ful sizes press. You can't put a full size press in your lap and work on the bow. The bowmaster allows you todo this with ease.