Brake pads 3mm left,Brake rotors get damage?

The life time pads have metal in them and ware down the rotors. Never get life time pads. Get the softest pads you can. My wife's car only had 40,000 miles on it and when washing it one day I seen a 1/4 in lip on the out side of the rotor where the pads had wore it down, Cheep steal for rotors and life time pads. This is some thing you can do you self, changing rotors & pads, The are lots of Forums out there to help you along . Now days they don't turn rotors , resurface them. New rotors for my wife's car were $25.00 each,and pads $20.00. I