I've always shaved on feel for the back of my head. Even when I used cartridge style. For me the trick with a straight is to know the feel of the correct angle. Yes I tend to have more touch ups in the back but not much. You can't really feel the hair as it is covered in soap. But I've learned a method that works for me. Just takes practice. An yes my reasoning for doing it was because a second mirror that's handheld is a pain.