Disc Brakes: Resurface your Pads?
You've met a mechanic that either wants you to buy more brake pads from his/her shop or doesn't know what he/she is doing. There's really no good reason to resurface your disc brake pads, let alone on a monthly basis. All that's doing is decreasing the life of your pads and temporarily decreasing your braking power until your pads bed back into the rotors.
I think that the reason some mechanics feel the need to resurface disc brake pads is a carryover from the need to resurface rim brakes, which do need to be resurfaced in some instances.