I would be interested where they found that information, I went through the Cessna Current manual today and bar the 50 Hr inspection it has no special requirements to replace the belts at 10 years, and the servicing section also simply calls for inspection, if there is any wear etc then yes, but a quick look I could not find any calender period on them, not trying to step on toes, just I have them on my approvals so was checking to see if I was missing something.