It has been mentioned many times by many posters that condition is everything. The odometer is not a reliable guide in my opinion as too many failures affect their odometers plus so many have been spun back. You might be looking at something with the original milage posted for example. It is not unusual to see a 123 for example on ebay with 300k posted that is in far better shape than one with a claimed 200k. Plus if you get a car someone has cared for even at high milage it might be okay. If the car has it's complete and accurate service records from the beginning is a real bonus as well. You will see what has been done over the years that should not fail soon. Otherwise you usually have no knowledge when the engine ar transmiison had a rebuild for example and what exactly was done at the time. A car with high milage and no information is a real gamble to some extent.