Similar to "Why does the new wear off..." I have also noticed that some balls are like magic for a short period of time when they are new, and others seem to just last a lot longer with the better pin action, carry, and scoring but even then they will slowly lose their scoring ability even if the hook shape and amount seem to remain the same.

My question is whether anyone has information on what happens to coverstocks and cores as they are compressed and rebound time after time from hitting the lane and hitting the pins.  Is there any information that shows the effects of use?  Does the friction, pounding and exposure to air actually chemically alter the coverstocks over time?  Or are balls pretty much inert?  My guess is the more exotic the mixture of resins used the more they are subject to change from outside stimulus.