My parents let me do just about anything (besides my piercings & tattoos - I had to wait until I turned 18 to get them). I had blood red, hot rod red, orange hair... in high school. I still got a job I now have piercings & tattoos... still have a decent job (they can easily be covered by clothing). I don't have any children, but when I do I'm sure I let them dye their hair, pierce, and what not. I probably won't let them tattoo until they're 18 - it gives them more time to really think about it. It lets the realization of how permanent a tattoo is really sink in.