Let's see...been coloring my hair for so long, that thankfully I have pictures that tell me what my "real" hair color ought to be :) :).
I have white gray hair over about 80% of my head, but for some reason I feel the need to color about once a month. DH has often told me to let it go, I just haven't come to terms with it. I just turned 51 so who knows...maybe when I'm 55, or 60--see I'm already hedging :)