DON'T - No matter how difficult the seller gets, or how much he or she insists their vehicle doesn't need an inspection, do it anyway. And don't fall for the old Uncle Harry move, when sellers "suggest" a friendly technician to conduct the exam. Always take your prospective used car purchase to an independent service shop, and make sure they lift the hood and take a good hard look.

DON'T - A negative vehicle is a red flag, and you should seriously consider walking -- very quickly -- away from the purchase. Examples include: Cars from natural disaster locales, repaired insurance "totals" (most titles identify salvaged wrecks), excessive mileage cars (more than 15 thousand miles per year), cars whose manufacturer has retreated from the US. Market, dramatically modified cars and vehicles from bankruptcy or law enforcement seizures.

DON'T - No certification, no sale. A certified used car has been reviewed by a technician and has met specific quality criteria.