I just shave by touch. Rubbing my hand around my face, I can feel the stubble to tell which areas need more attention. How do you think blind people shave?
I do not use a mirror, shave by touch, I guess I have tough skin, I never have a problem with cutting or bleeding even when I used the blade for 4 months, it just quit working without resorting to multiple passes (like 6 or 7) over my face
I switch my mach 3 blades about every 6-7 uses. Guess I have a rough beard. I got a couple turbo blades after I replaced the razor itself but haven't seen much of a diff.
I also shave in the shower with a fogless mirror. That, combine with using a badger hair bristle brush & shaving soap from "The Art of Shaving" makes things so much more pleasant. The great thing about shaving soap is that it doesn't contain any alcohol, is way better for your skin and even with the higher initial cost (~$15), it comes out as cheaper as I've had my 1st "bar" for almost 2 months and I'm not even halfway done w/ it yet.