Hi. I learned to cut my own hair by figuring finally (!) that I could do it. But I am now doing the single-length style, meaning I don't layer it in particular. I tried layering but it was too much trouble. I just cut a smooth straight-as-possible cut. I don't need a mirror to cut the back, because I kind of feel or know where I'm going with the scissors. Yes, sometimes my hair gets a bit tangled with the mask. In a way, it pays to let it grow longer so I can pull the hair back, but I'm not particularly worried about that. Because I like to wear earrings and I like them to show. 🙂 So -- time will tell.
P.S. I do know someone who bought the metal thing to cut her own hair but she has a very short cut and apparently needs help to sculpt it. But she does a good job on herself. I don't want a very short cut right now. You're convincing me to let my hair grow longer. 🙂 Take care.