May be a difficult one to answer but here goes, My 2012 350 diesel just turned 80,000 km. Out of this I think about 40k was towing a 8k fiver for three years and this year a 15 k toyhauler. Thinking ...
This past summer did a complete brake job front and back as well as e-brake, one rear caliper(cracked piston) on my '06. Truck was on the original rotors but I had changed the pads out on front and back several times. Truck had close to 300k kms.
Treat the brakes right and use the T/H on these trucks and the brakes last a LONG time!
Replaced with Motorcraft rotors since the originals did so well.