Coloring your hair at 50 isn't all about covering gray. We dye our hair to fatten up thin locks, amp up our skin's glow, soften the effect of wrinkles and make a so-so haircut rock. And as for gray, we hit the bleach to help grays grow in and to make them more luminous when they do. Hair color can make all the difference between looking delish or drab. But which color? That depends on your skin, hair health and wallet. Here's how to choose the best next hue for you.