Some sort of medicine or ointment or balsam or whatever that halts hair growth. You decide your hair looks good right now at that length, and use this stuff to freeze its growth. It also protects your hair obviously so that it doesn't get weak and fall off.
Another thing I'd like is some sort of bath salt type thing that dissolves in water and painlessly removes all hair. You get in the tub with only your head above water, and then enjoy a smooth body without annoying-ass hair or annoying ass-hair.