Nothing wrong with waiting until the squeal unless you are going to be doing some towing or maybe mountainous driving. Totally up to you.
Resurfacing...as long as all they are doing is taking off the glaze from the previous set of pads it isn't a bad idea. It doesn't hurt to get the glaze off the rotors so that the new pads bed in correctly, but you don't want them turning them down and taking material off the disc unless they are warped. I hand sand the rotors to take off the glaze. That's all that is needed as far as resurfacing is concerned.
Resurfacing...as long as all they are doing is taking off the glaze from the previous set of pads it isn't a bad idea. It doesn't hurt to get the glaze off the rotors so that the new pads bed in correctly, but you don't want them turning them down and taking material off the disc unless they are warped. I hand sand the rotors to take off the glaze. That's all that is needed as far as resurfacing is concerned.
