Take the driver side off and look at the general condition of the belt. I do that every few years. Where did you see the interval of replacement of 10 years in the FSM? I only see at 60K mile for TT, no time requirements. Also for the NA newer years 94+ FSM lists 105K miles, again no time requirements.( note 5)
If the belt has been exposed to any fluids, I'd be more concern and replace it. If nice and dry but still pliable, I wouldn't worry too much.