Really depends on how you drive, traffic conditions and how you brake. For example, I have driven cars with OEM pads for over 150,000 miles before I had to replace pads and turn rotors. Likewise, I bought a Xfire with under 15000 miles and had to replace the rotors on all the wheels when I put on Rotex pads. So as you can see it is difficult to give you a valid average. Best thing to do is pull the wheel and take a look at the pads and rotors.