I have an Audi A4 with approximately 35k miles. My dealership has recommended that I replace both the brake pads and the rotors and helpfully forwarded a picture to me of the rotors indicating the rust around the edges. My understanding from doing a bit of research is that the rust itself is nothing to worry about and the surface area of the rotors do not appear bad at a glance... but I'm no expert. Thoughts?
Rotor replacement is normally done when the rotor can no longer be resurfaced and still fall within the acceptable thickness range. The acceptable thickness range is based on stock brake pads though, so if you're using more aggressive aftermarket pads you may have to do replacement rotors sooner than is specified.
That rust on the edge doesn't concern me since my rotors look like that within weeks of installation on my cars. :-)
That isn't mostly rust buildup. That is the edge of the rotor that your pads don't touch. If it feels raised then that just shows you how worn your rotor is.
You do not always need to replace rotors with pads, but it looks like you'll be replacing them next time at the latest.
I once had a rotor split while driving home from 6 hours away. When it cracked I was riving 60mph on a State Road, the crack seized the rotor when it caught on my pads. My rear tire locked instantaneously on a double lane, driving 60mph. Sliding through traffic isn't fun, and neither is changing rotors on the side of the road.
If you're concerned about money, call your dealer and tell them that you want them to use lifetime warranty parts. I they don't have any lifetime warranty rotors, tell them you will provide them with some. You can get them at any auto parts store and they don't cost much more. Autozone charges me $2 extra per lifetime warrantied part. Then when it naturally wears out, they'll replace it for free.
Worst case, changing rotors is literally one of the easiest tasks to do on a car, it's definitely one of the simplest. You can do it yourself if you want to save some money, but do it right after getting the pads or you'll sacrifice some of the pads life as well.
Replacing rotors or drums every other time you replace the pads/shoes is crazy. For most daily drivers, that would be every year or every 2 years. Unless the vehicle is being used for something like a delivery service (IE, LOTS of miles with TONS and TONS of stops), there is no reason not to expect 50K-100K or even more from a pair of even stock or OEM-equivalent rotors/shoes. And the front brakes will always need more servicing than rear brakes, usually anywhere from 2 to 4 times the frequency. But the first rule is always to INSPECT the condition and service as appropriate, no matter what "rule of thumb" you're fond of.
If your rotors' wear surfaces are still smooth & flat & true, then keep the rotors and replace the pads alone. The dealer wants to replace the rotors because doing so eliminates one potential source of liability for them - the more they replace, the less their potential liability.
If the wear surfaces are NOT still good, then they should be measured to see whether it's practical to resurface them (provided that shop still owns a brake lathe - brake lathes are rapidly becoming extinct). If too thin, or if no brake lathe is available, replace the rotors.
But... that band of rust is NOTHING. It's not even enough to make changing the pads difficult. It's... a waste of metal in the first place.
35K seems awfully early to be replacing pads, though... do you rest your foot on the brake pedal a lot while you drive? Does your driving include a LOT of stop-and-go city traffic? My wife & I both drive '07 Toyotas, and both are still equipped with the original brakes.
You've already got your answer, but I'll just add that as a rule of thumb, you should replace your rotors with every second pad replacement. Also, rotors can and should be skimmed when fitting a new set of pads. It restores a nice smooth surface. It's not a MUST, but it's a very good idea.
If you have drum brakes at the rear, it shouldn't ever be necessary to replace them. Unless it's a very high mileage car. Drums last extremely long and even the shoes tend to last more than 100k miles. This is just on tiny cars like the Ford Fiesta.
