I had a caliper not releasing enough away from the rotor on another vehicle and went thru a set of brakes in less than two weeks. It was in the caliper slide and not the piston.
Calipers have glide pins that need to be greased when changing pads or adjusting brakes.
Overheating the breaks will cause the grease to melt away allowing for water oxidation and rust.
Also be sure it isn't the parking brake.
Or the dust shield rubbing.
Update. New brakes today. Did them myself and a friend this time. 2 pins froze and not moving freely. Rear inside pads were completely gone. Cleaned and properly lubed pins. Brakes work great now.