as always, apologies for english...I understand dutch, but writing is not my strongest point!
As mentioned before, it all depends of maintenance of the scooter. Once I was buying my Vespa LX50cc 4v 4t in 2009, I had the same thought...how far can this engine go. Today, after 14 years and almost 60 000km and regular maintenance it is still running hard. I have notice that it starts more difficult in cold weather. I have the idea / goal to try to reach 100 000km..but now it is a question if the frame will make it...
good luck with buying!
Dusan, Haarlem