You should probably include the cost of your time wrenching on the car which most people seem to ignore. But if you enjoy working on your car and you should probably subtract that time from the equation. Then again if you enjoy working on a car but run into a problem that you really hate... then it gets complicated. This is all a little too OCD for me. All I know is fuel costs me 9.5 cents per mile plus $500 in parts since I bought the car 10,000 miles ago. Thats as far as I'm going to take it.

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CENSORED due to not family friendly words