I'm soon 39 with maybe 20-30% grey. I've dyed it at home for some years, at sporadic intervals, but it was such a mess and a hassle, I felt. Once I could afford to get it done professionally I was so pleased with the results and the compliments that I deicded to treat myself to it 4 times a year. That way it still grows out and I'm reminded what I really look like but I get to feel real pretty at regular intervals

I'd prefer to have the grey show, but not just as a "helmet". I'm working on it - next time I'll try having it cut shorter and having greyish stripes.