how does one tell if rotors need to be turned?
 

I'm about to try changing my own brake pads for the first time (yeah yeah I know, I'm just getting in to doing my own maintenance), and I'm curious how to tell whether the rotors need to be repaired/replaced? The one time I've had my brake pads replaced before (on a different car), the mechanic told me that the rotors needed to be turned. I'm not sure whether that was BS or not, but if it was legit then what are the signs that the rotors are in bad shape?

Thanks,
Andrew Reeves

Good idea to measure the rotors against spec. It should be imprinted on the edge of the rotor.
 

Normally if the rotor is still within spec you're OK to just drop in the new pads.

If you had issues with brake judder or if you are switching types of pads, like metallic to organic, it's not a bad idea to resurface them. Have them take off just enough material to give you a fresh bedding surface.