What's the downside of replacing pads without milling the rotors? Back in the old drum brake days, we used to buy rebuilt pads for a shade tree install and never gave a thought to turning the drums (as long as the wear grooves weren't too ridiculous). I suppose there might have been some marginal loss of braking power until the pads seated completely, but I never could tell any difference--they'd lock if I needed them to.

By the way, how many miles should do front pads (the standard soft variety) tend to last on a 107?