@Neil, I repaired during last four years around 25 scooters, mostly KYMCO.
All of them had between 18000 and 60000 kms on the clock.
Neither I nor the owners did have any "belt-problem" on this scoots.
None of the scoots were one-owner pieces, so noone really knew whether the belt was changed or not.
The old saying comes up, "better save than sorry" and change this €50-100,- part.