I understand that the rotors need to changed with every change in pads or at most every 2 brake pads, but is this really necessary? I noticed there is a lip on the rotors of my 2004 Disco which has 39k miles, but this seems to be par for the course for these soft rotors.....should I change them or just replace the pads?

Might just be me, but shelling out a bundle of cash for pads AND rotors at only 40k miles seems a little excessive.

 

I don't change mine till they are warped. My current set of DBA rotors has nearly 80,000, on the same set of pads, the brakes are fine. When they start to shake, because of warped rotors then they need to be replaced.