This may be a noob question i will go ahead and ask it. In the several years I have been playing tennis, I still dont know why strings simply "go dead". I know why they loose tension and break and I know what happens when they go dead (loose feel,pocketing,elasticity) but I dont know why they go dead (other than constant use). I alos know it is time to get a new string job when they go dead but it would be impossible to explain to my parents for the constant restringing. They think that if a polyester does not break and does not loose tension, it can be used forever. Can somebody help me out and explain this to me. Also what determines the life of the string.