How many years will I own my car? How do you know? You amortize the cost over the planned lifetime. If you keep the car for longer than planned, great, you get

How many years will I own my car? How do you know? You amortize the cost over the planned lifetime. If you keep the car for longer than planned, great, you get a free usage extension! If you need/want to replace the car sooner than planned, you need to factor the sunk cost of the previous purchase into the cost/benefit equation of your next.