|Be sure to loosen your bow every time you put your violin away. The same way your body needs to relax, the bow needs the tension to be taken away when it is not being used. Not only does it prolong the life of the bow itself, it also prevents the hair from stretching.
Also, most violin bows are made of wood, just the same as your violin is made of wood. The same basic care rules that apply to the violin apply to the bow. Be sure to wipe rosin off the bow at the same time you wipe it off the violin.
Take care of your bow! It really is more than just a horse-hair-holder!