I've been looking into this for several months. I have studied several websites & read a few articles. I am convinced it is more than "hardening" , in fact, I dont think it is hardening at all, but something that allows the structure of the atoms to realign somehow & be stronger. Whatever the mechanism is that alolows it to make things hardier, regardless of my understanding of it or lack thereof. I dont see it as voodoo or the equivalent of this weeks winners "fad". It has been being done too long & by too many people. When commercial fleets go to it, yo9u can bet they didnt just start doing it on all their fellt at one time. Would YOU, as maintenance foreman, just start spending $$ on every brake rotor in the fleet or would you do it a few vehicles & compare service life to the untreated ones? Duhhh,, doesnt take long to figure this one out. All that is required is to have a scientific mind instead of a cynical one.