BigCarrot,
It is very difficult to know/learn the history of a car that has been owned by multiple persons. If your buying off the original owner, you can drill him with questions that he must answer, and can't say, 'Not to the best of my knowledge" or "Not since I owned the car", etc... Of course, your gut should tell you whether the person is being honest. Also, 'most' private sellers don't want you coming back after the sale, due to them lying about an accident, paint, etc... Some people even create contracts that stipulate certain factors, to protect this huge investment. These things would be very difficult to accomplish with a 3rd or 4th owner, or purchasing from a dealer. They always have an out, and can blame things on a previous owners. Not saying I wouldn't buy off a dealer or 3rd - 4th owner, but 'best case scenario' would be a one owner car. Personally, I would pay a premium for a one-owner car.