Wondering if it is necessary to change rotors every time we change pads.My rotors don't seem to be warped or glazed up.

 

No, only is they are below minimum thickness - or warped as you mentioned. Glazed rotors can be scuffed easily to remove it.

 

Should they be resurfaced?

 

Nope.
Current thought is either use them or replace them.
The era of turning rotors is more or less over. Rotors have gotten cheaper so the quality does not normally allow for a good turning. They are inexpensive to purchase if there are any defects or are worn.

 

Even though my rotors are within thickness specs, brake shop says they need to be replaced because they have a lip on the edge. Is this true? I hate to have to spend $350 on new rotors (JCW) every time i change brakes!

 

IMO the shop sees a fish on the line to buy a set of rotors. I wouldn't.

sure there is a lip, if you've been running pads - that is, the rotors are not brand new - then the pads have been wearing the rotors, essentially grinding them down. No pad extends all the way to the edge of the rotor - none I've ever seen anyway and I've been playing with cars for nearly 40 years now. The grinding causes a lip to develop. This is natural. MINI develops a lip faster then many cars cuz MINI eats brakes faster than many cars. MINI engineering says soft materials means greater grip and there is logic there. Of course some say they use soft materials just to make you buy parts more often . . .

My MINIs eat pads at about 35,000 ... My Miata still had the original pads at 100,000 and I changed them cuz I couldn't believe they were still good. They were about 60% worn, the rotors had a minimal lip. My Honda ELEMENT is nearly as good, the front pads went 95,000 and the rotors show minimal lip, I changed the rear pads just cuz - they were probably less than 50% gone.

If you are using/replacing with the same brand of pads then they sure will be of the same size and I'll guess there is no problem. I've even changed brand of pads and used rotors with a lip, never once have I had a problem. IME on my MINIs I can go two sets of pads to a set of rotors; ensuring the pads had no scoring and there were no signs of warpage. I use EBC Greens exclusively. But in both cases, a 2002 and a 2007, I ran factory pads for a while and a lip sure did develop, but changing to EBC Green was no problem. I've made the same change for others several times when their first set of factory pads wore out - changed them to EBC Green using the same rotors - and no one has had a problem or complaint. But no one has tracked the car either . . . I'd not even say any were hard drivers.

 

When the rotors get a pronounced lip on them you can grind a bit of a chamfer on your pads to get them to contact the rotor at the outset.

You can also do as I do and install them untouched and then drive around the neighborhood real carefull braking several times until the pads grind away to match the rotors - then proceed on to the bedding process.