I have a Subaru Forester 2011. Yesterday I noticed passenger rear wheel is extremely hot and has a burnt smell, and sent the car to my mechanic. Today he told me he did not find anything wrong with the calipers and the pistons move well. The only thing he suspects is the brake fluid is dirty and need to be replaced. However as my calipers are in warranty, he will replace the calipers anyway. But he said I also need to replace my rotors.
We stay with this mechanic for five years since 2015. In 2018, I had front calipers and rotors replaced. In 2019 I had rear calipers and rotors replaced. The car is used by my wife and I for daily commute and we have ~8000 miles/year. So I asked him why the rotors need to be replaced so soon. He said he did not know and he said "Maybe it's your driving habit". My wife did do hard brake sometimes. But I doubt if that will cause the rotors to wear that much.
My question is: Is it possible for a rotor to wear out in one or two year after driving only ~15000 miles? Is my mechanic cheating on me and should I go to another mechanic to do a check next time?