When I see those things I think of Floyd the Barber on Mayberry, more specifically the skit on Second City TV where he was always checking the artery chart behind the customers back while he attempted to shave them or should I say cut them.
I also shave my head and I am usually in too much of a hurry to be careful enough not to slice myself open. I actually get a lot of mileage from those disposable razors; I use them until they really don't cut the hairs anymore and just start to pull on them. But yeah, they are expensive.
But just wait until they come out with the Track 10!