"Grey," the British spelling, is just so much prettier to look at than "gray," don't you agree? No? Keep it to yourself.
I have lots and lots and lots of well-earned grays and naturally very dark hair, so as soon as they come in they're like little 2" sparklers poking out along my part in celebration. I get my color done at a salon because... gosh, come to think of it I'm not sure why I do that? It's a single process and just a root touch up, I should really be doing this at home. [Note to self.] Regardless, my roots need covering about every six weeks, but they only get it every two or three months. In the meantime, I do one of two things:
1. Stay home and don't let anyone look at me, especially people who are taller than me and have a bird's eye view of my dome. Conversely, if I must leave the house, I'll wear very high heels.
2. Spray my part and any other visible white hairs with this colored powder from Bumble & Bumble. It has its pros and cons, but compared to those makeup-like gray-covering sticks or cremes, the cons are more tolerable (to me). On the plus side, application is SO easy, it's just like applying hairspray. And the color lasts pretty much until your next shampoo. Negatives include maybe slightly tinting the floor of your bathroom (stand on a towel) and your pillowcases. It washes out, but still.
I only have experience with the black and brown formulations for this use. (The white powder is more like "clear" and is a great dry shampoo, once you brush it well.)
As we like to end all posts around here: it's dumb expensive. BUT! It lasts forever (I've had my large can for two years now? Maybe that's gross?) and it comes in a travel size for a little more than half price.