From a Colorist
Anyone who frequently dyes their hair knows that washing it too much can dull your color. That's why as a general rule, colorist Stephanie Brown said these people shouldn't wash their hair more than every other day. "If you have drier hair, try waiting a little longer. You want your hair to absorb some of your natural oils so it's strong and shiny," said Brown. "If you feel like you need to wash your hair more often, use a substitute, like the cleansing conditioner Unwash ($29). These don't strip the oils out and add moisture."