You have answered readers’ complaints about rapid wear of brake discs with an explanation that corrosion due to light usage is the cause. Whilst this has a small effect on disc wear this has always been true. The main reason for current high wear rates on modern brake discs is the use of alternative aggressive high abrasive pad compounds developed since the much gentler asbestos based compounds were banned. White asbestos was by far the best material for brake pads and linings but unfortunately it was linked with the dangerous blue asbestos and manufacturers were forbidden to use it. White asbestos is an entirely different chemical to blue asbestos and it is perfectly safe to reintroduce. Unfortunately this is extremely unlikely given the adverse publicity continually put forward by the anti-asbestos lobby. We shall have to continue to grin and bear the consequences of this misguided legislation for a long time yet. The cast iron used in the manufacture of discs is of inferior quality these days, which also doesn't help.