I've done that to keep a beater car on the road a little longer, but if you're driving the car hard, I would do a proper job. Remember that it will take much more time for the pads to wear in to the old rotor if you don't have it turned or replaced. Also, check the wear indicators on both sides of the rotor and reach inside to feel the inboard side. the inboard side may be worse the the side you can see. If there's not much life left in the rotors, it makes no sense to slap pads on, then replace the rotors in 6 months or a year.
