Thou shalt not subject hair to more than two chemical processes.
Thou shalt relate to thy skin tone.
When in doubt, peruse old family albums. "Stay close to the color you had when you were young," says Rita Hazan of the Rita Hazan Salon in New York City. "It will always be the most flattering on you."
If you plan to reclaim a towheaded youth, however, don't rush in. "Even at the salon, your hair will lighten only so much at one time—push it too far and it turns orangey," says Hazan. "Do a little every month, so you can control the brassiness."
Remember Thy Brows.
Never match your brows to a new haircolor, but consider making them a touch lighter or warmer. "The whole eye area can look younger and softer," says Bumble and Bumble color director Victoria Hunter.