I get between 5-6 shaves per Mach3 blade--which, because at the weekend I generally shave Saturday afternoon or evening, gets me through the week. And I shave my head as well as my face. In light of this longevity I can't really complain about the expense of the blades, as Sensors (my old favorites) couldn't be pushed beyond 3 or 4 shaves (and I've got a heavy beard for a blond guy). I've been wondering about the Mach3 Power--does the battery make all that much difference? I've got a mania for a super-close, baby's backside shave, so if anyone can tell me it helps, I'll probably bite.