You might get suspicious if the mileage is too high or too low, since a normal average mileage per year is about 15-20 000 km. But of course, it depends, and I agree it’s better to be cautious and double-check. You can check the mileage through a VIN report, ordering one on FAXVIN or other alternative services. If everything matches, great. If not, you save yourself from a sketchy purchase and wasting a lot of money. 

   What should I even pay attention to as a buyer? For example, I’m checking out a car, I see the mileage. Why might that make me suspicious? How can I tell if there are problems?