I have been told by dealerships and repair shops that they will only replace pads with new rotors, and/or sometimes only after turning the rotors. In this day and age of everyone getting sued for every little thing people can think of, changing the rotors with the pads is the most fool proof conservative way to do a brake job. But I do think it is overkill.
I do my own repair work and I usually just change the pads if the rotors are still good (not warped and pulsating). If the rotors are pulsating, I would be OK with turning them once as long as they are still in spec after the turn. They only take a couple thousands off the rotor when they turn them so it's not like they are removing half the thickness. But they do tend to warp after you have them turned, even with the small amount taken off.
I have also found that if you go to a local parts store (like an O'Reilys Auto Parts) and get their lifetime warranty rotors that they have been very good and sometimes are not much difference in cost than having the rotors turned, or close enough that it makes sense to just put new ones on.
I have brake jobs where I changed rotors to new, or just turned the rotors, and I've done just a pad change and left the rotors as is. No matter which way I do the repair, I still get full braking power. I just do a couple fast stops from about 45 mph to get the pads seated well, and they seem to work fine. Again, to be clear, I do think turning the rotors or replacing them results in a better brake job, but I think the difference is negligible for all practical purposes.
I have found the Wagner Thermoquiet pads are excellent. No brake dust, they stop well, no noises or problems, and last very well. Lifetime warranty also.
One last caution. I have in the past changed only the pads that needed to be changed (such as just the front, or just the rear), but I don't recommend that. If the pads you get have more or less friction than the pads installed, you will shift the braking force (and thus the heat) to the pads that grip the best. And that results in that set of rotors or drums getting hotter than they should.
Also, it changes the braking force balance of the car/truck, so it could make the rear brakes lock up before the front brakes and cause an accident. Or it might shift the braking force more to the front resulting in front wheel lock up with less braking force from the rear, resulting in longer braking distances.
So, when you do a brake job, do the front and back at the same time with the same brand of pads.
I do my own repair work and I usually just change the pads if the rotors are still good (not warped and pulsating). If the rotors are pulsating, I would be OK with turning them once as long as they are still in spec after the turn. They only take a couple thousands off the rotor when they turn them so it's not like they are removing half the thickness. But they do tend to warp after you have them turned, even with the small amount taken off.
I have also found that if you go to a local parts store (like an O'Reilys Auto Parts) and get their lifetime warranty rotors that they have been very good and sometimes are not much difference in cost than having the rotors turned, or close enough that it makes sense to just put new ones on.
I have brake jobs where I changed rotors to new, or just turned the rotors, and I've done just a pad change and left the rotors as is. No matter which way I do the repair, I still get full braking power. I just do a couple fast stops from about 45 mph to get the pads seated well, and they seem to work fine. Again, to be clear, I do think turning the rotors or replacing them results in a better brake job, but I think the difference is negligible for all practical purposes.
I have found the Wagner Thermoquiet pads are excellent. No brake dust, they stop well, no noises or problems, and last very well. Lifetime warranty also.
One last caution. I have in the past changed only the pads that needed to be changed (such as just the front, or just the rear), but I don't recommend that. If the pads you get have more or less friction than the pads installed, you will shift the braking force (and thus the heat) to the pads that grip the best. And that results in that set of rotors or drums getting hotter than they should.
Also, it changes the braking force balance of the car/truck, so it could make the rear brakes lock up before the front brakes and cause an accident. Or it might shift the braking force more to the front resulting in front wheel lock up with less braking force from the rear, resulting in longer braking distances.
So, when you do a brake job, do the front and back at the same time with the same brand of pads.