During oil change at 67,000, dealership said I needed rear brake pad replacement and rotors resurfaced. Next oil change at independent shop 72,000 was told all brake pads will need replacement by 77,000, and that I’ll probably need to have rotors machined. I’m fine with replacing pads (is it best to do OEM pads?), but why the emphasis on rotors? Consumer Report’s Car Repair Encyclopedia says symptoms of needed rotor service are pulsing, noise, grinding, and/or difficulty stopping. None of those symptoms are present and braking distance is still excellent. I’d appreciate thoughts/advice - thanks.
Pads and rotors develop grooves. Your old pads match the groves on the rotors. New pads will contact the surface of the grooves which may reduce braking ability. Replacing the pads without new or resurfaced rotors can be done, but is not advisable.
Run away from the dealer and find a good local mechanic. Almost no shop, dealer or otherwise, resurfaces rotors anymore. They replace them for the same cost as the machining fee. It is now standard practice to replace rotors when pads are due for servicing (replacement).
Concur w/GJ above, get new rotors (along with new pads) rather than resurfacing. Rotors that come on newer cars like your aren’t usually thick enough to resurface safely. On older cars its possible, but I wouldn’t advise it on a 2016.
If you purchase OEM pads from the Mazda dealership you’ll likely get good results, but many aftermarket brands will give you equally good results. There are various shims and anti-squeal gadgets that usually come w/the pads. Failing to install those parts, or installing them incorrectly is a common cause of squeaks. So make sure the shop intends to do that part of the job for you.