Look how some used cars with a really big mileage look like.
Just have a look, those are some examples of a big enough mileage. So, once you will go to a car outlet and see one with 149.000 km. on tachometer indicator, just compare it with the ones below, which have a totally proved history of ownership, mileage and tehcnical service.
Audi A3, year 2007, 4 owners (2 companies a 2 private owners), 3 of them were in Prague. The mileage is 253000 km.
Even more interesting.. Hodna Civic, year 2008, 3 owners, all of them in Prague, 293000 km