There are a lot of guys who do it themselves. Till I moved to the mainland from Hawaii. ever man I knew (atleast the ones over 35) cut their own hair themselves with clippers. I have a high and tight because I was in the Army at Ft Jackso for a long time and that was THE way to have hair, some guys use the longer gies on the top and the shorter ones to taper the back and sides. There are some pretty good guides on You tube. It you use just one size guide you will look more feminine, kind of like Annie Lennox, or if you have feminine features and you cut your hair too short, it actually emphaaizes those feminine features. Maybe you remember Sinead Oconner? No hair was more feminine than long hair on her. If your skull is just weird shaped you could wind up looking comical. Sometimes its best to get the barber's or a men's stylist's opinion on what would work for you. Its also got to fit your lifestyle.