Brake rotor wear

[Frodo]

Getting ready to do my first brake pad replacement. PO must have done the fronts before I bought the car, since I have more pad material in front than in the rears, so at the moment I'm just doing rear pads.

At one point maybe a year ago I took the car into a dealership so we could put it on the lift and he (& I) could take a good look underneath. (I had been doing most all of my own regular maintenance and I figured I'd have someone more knowledgeable than I at least inspect things for a change.) He had several suggestions that I won't go into here, but at one point I asked him about the brake rotors.

I asked because, obviously, the pads wear into the rotor and in doing so leave a narrow "lip" of material at the outermost edge of the rotor. He said I shouldn't have the rotors turned, but I could take it to a machine shop or brake place and have them just take off the lip. In the alternative, he said I could bevel the new pads a little for fitment purposes.

Now that I'm about to do the pads, looking back on what he said I can't really understand why he said that. Don't the new pads just fit into the worn area of the rotors? Or are they shaped slightly different depending on who made them? (I've had no complaints about braking---I'm inclined to just use the same brand of pads.)

BTW, the lip is about 0.5 mm each, inside and outside. The rotors are at about 23 mm, and the spec service limit (Bentley manual) is 18.6 mm, so they should be fine without replacing I would think. The car's got just over 65K miles on it.