I sometimes cut Mrs Growster's hair, and years ago, bought some professional clippers, which make it easier if I'm doing my own...
They have the numbered combs, which stop the worst effects of inaccurate cutting, and the back is pretty difficult, but as long as I can make the sides give my glasses some space, I guess it's a result of sorts!
Trouble is, I like our hairdresser, and get much of the village chat from her, but of course, they're closed...