Brake rotor life ?

If you take the wheel off, you will see the minimum thickness stamped on the central part of the disc (rotor). As long as they exceed this, and are not unduly scored or warped, stick with them!

I typically get 2 sets of pads to one rotor both front and rear .... front rotors go 35k to 70k miles on my 850's depending on ratio of city to highway driving and rear rotors go 50k to 90k.

Make that 35k to 50k for PADS, and 50k to 90k for PADS (sorry for the goof where I said rotor instead of the PADS that I meant).

Pretty much the same for me (S70, same brakes as the 850). Rear pads lasted

I downshift when I brake (heel-and-toe... manual transmission... yay!), and this helps the brakes last longer. Also, almost half of my mileage so far is highway.

I know the rotors will last two or three sets of pads, but I like to replace them with the pads anyway, since they're scored and rusty at five or more years old. That's just my preference, and it isn't too much more expensive since I do my own work.

When I had taxis I used to heat up the discs if they had warped and then let them cool down slowly as often drivers had punished the brakes then stopped and switched off while they were extremely hot,so they warped.When I needed to have the rotors machined (which was very rarely) again I would hot them up cool them down slowly then have them machined as this removed the grain effect ,otherwise as soon as newly machined rotors heated up they would warp if cooled down slowly back to their old grain or shape ,or just buckle again if left hot .When buckled the machined took off the highs making all level but the lows became highs when heated up again .Hope this make sense as it saved me many dollars from sometimes greedy mechanics .ALWAYS USE QUALITY BRANDED PADS AS CHEAP PADS COST and are not as safe ..And change your brake fluid to at least a quality branded type every 2 years or so ..