A man with no eyes, living in a cave can see that with poor quality products and poor washing techniques, you're going to inflict enough damage on your paint to make it look like it's done 50k miles when it has infact only done 10k
The value of second hand cars is largely determined by the condition of the bodywork. Yes, you're right in saying dents and stonechips also effect their value, as do scuffs on alloys, but with all things equal regarding mileage and service history, 'car a' has well conditioned and looked after paintwork, and 'car b' has been subjected to the Polski butchers then 'car a' is going to be worth SIGNIFICANTLY more. This is a fact, not my opinion. if I can add £800's worth of value to a 10yr old Honda Jazz, then how much would I add to a nearly new Porsche Boxster?
Answers on a postcard.
I accept you're a none-believer, but you carry on doing what you do Mr Hans