Not only torque, as Hutch suggested, but dirt and grit. When a slide starts grabbing (chattering) it's usually caused by either water, as shooting in the rain, or just plain old buildup of grit or dust. Make a concerted effort to clean the rod once in a while. A soft cloth or paper towel and alcohol will do just fine. If you can force the slide off the back end it wouldn't hurt to clean the inside of the slide the same way, but with a QTip. This should take care of the problem as far as the dirt is concerned. As for rain or snow, the best solution for this is just a good Teflon slide.
In any case it's always wise to inspect any slide once in a while. Before even installing one take a good look at the edges where the cables will ride and chamfer any sharp edges with a little rattail file. This will help ensure longer cable life.
Any rod will wear over time, but these suggestions shold minimize it. A carbon rod should, with care, last for many many years.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver