mileage is just one indicator of how much the car's been used. but just like any other things, it's performance depends on its maintenance and if it ever had any problems before. so do check the service records of the car.

my car has potentially high mileage. barely 2 years it's already pushing 55k. so i keep every receipt during service and parts replacements, so that when i sell the car, the buyer can see that i kept it in good shape, replaced everything that needs replacing before it broke down etc.