Just try to buy a vehicle from someone who u can trust,
and u can calculate the annual mileage from the owners home place of work, number of children, how many vehicles he has ect....
some times the condition only can't tell the millage,
car sales bring down vehicles having 100k+ on the odo change it to 8k paint polish detail it to look better than a genuine 20k brand new bought car and sell it for more.