I've replace a couple now. It seems that both cases the cable wore out the plastic pully wheel until failure. My guess it might have something to do with how hard the system is working when operating your windows. I.e. I would have to imagine it works harder with dirty windows, ice or anything that would affect the ease of movement up and down as well as any debrise (dirt and grime) build up on the actuator cable, which could become an abrasive on the wheel. Just my $.02.