I never have. I was never rebellious in my youth and as an adult have never felt the need.
This is helped (a lot) by the fact that I have that Scandinavian kind of blonde hair naturally, and that at 56 it hasn't yet started going grey. I appreciate that in different circumstances I may well have decided to colour it, but I can't be the only one. 'Everyone' seems to assume my hair is dyed, including hairdressers, on occasion!