I have operated an old C-150 with rotors so corroded, grooved and pitted that I would'nt even want them on a boat trailer and they provided normal braking, although they would eat brake pads at twice the normal rate.
Be sure to not cause a brake fire when "bedding in" the new brake pads. On a piston single I would only perform 2 to 3 "aborted takeoff" type braking manuevers from 30-40 MPH to bed in the pads then let the brakes completely cool. On a heavier aircraft ony perform one high speed brake application between cool down periods. I have seen more brake fires from pilots bedding in brakes by riding around the airport dragging the brakes for too long, or to many consecutive "high speed" taxi brake applications than any other cause.