There are plenty of people who take care of their cars. Their old cars are in the CPO section of used car lots and priced accordingly. Short of actually being

There are plenty of people who take care of their cars. Their old cars are in the CPO section of used car lots and priced accordingly. Short of actually being able to look at a vehicle and assess its condition directly there is no free lunch. Any "signal" you can use will also be used by everyone else and the dealers will price it in.