One of the most important questions to ask yourself when considering how often you should wash your hair: How often do you want to wash your hair?

If you can't stand to go more than a day or two without reaching for the shampoo bottle, it's cool. "With the vast array of shampoos and conditioners available for every hair type, it is perfectly fine to shampoo daily," says Fusco. Tanzi is a fan of every-other-day shampooing, suggesting "three or four times a week" is acceptable for most hair types.

If you swear your hair is better behaved with infrequent shampooing, that's also fine. Just make sure to wash twice a week. "I don't recommend going any longer than three or four days," says Blaisure. "This is likely to cause scalp problems."

And definitely don't expect a trichologist to sign off on your no-poo routine. "After all," says Kingsley, "You take your hair and scalp to the same places you take your face, and they get just as dirty by the end of the day."

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