Volvo Repair: Brake rotor replacement, 2005 volvo xc70, brake rotor replacement

Question
I have a 2005 Volvo XC70 with 54,000 km. I just took it in for servicing and was
told that it had only 10% left on the rear brake pads and recommended that we
replace both rear pads and rotors, which we did. My question, after the fact, is
this rotor replacement normal and necessary?

Answer
  Bob, short story, yes. If you resurface Volvo rear brake rotors, you will often get an annoying accompanying squeal that nothing will fix but replacement. I never did figure out why, I just know that it is so. 30 years of working on these critters teaches you a lot. Sometimes "why" is not as important as "how" to do it right. I have learned that only "Balo" brand and Genuine Volvo rotors are to be used. Anything else is a crapshoot. They both have a non directional finish on them. (Not cut like a vinyl LP, but cross hatched) This works! Use ONLY Genuine Volvo pads also.

Mark