I understand that bit, just thought they had a different disc that would withstand the metal on metal for longer. I don't know what is normal but I think with past cars I've usually gone through 2/3 sets of pads to discs, but i'm not a heavy braker either. I once got 20 miles into a journey and wondered why my cruise wouldn't come on in the Astra and it was because I hadn't touch the brakes. Eco driving/ light wallet for you