Remember that girl you went to high school with who once told you that if you washed your hair every day, it would fall out? Yeah, she was lying—and probably just jealous of your beautiful hair. But why rehash the past anyway? There will never be a scientific consensus on how often is too often. For now, there are testimonials, experiences, and shopping lists to help guide us toward perfect bedhead. ITG has been asking its interviewees for years, and the answers vary. Why not collect them and cherry-pick your favorite tips? Starting with the inimitible Cindy Crawford and working our way through the Pantheon:

Cindy Crawford

"I don’t wash my hair as much as I used to, only two or three times a week. I have a blow dryer and I will get blowouts, but it can break easier so I learned how to make it last for three days—I pin it up when I sleep or I will pin it up when I work out. I kind of go between two shampoos. If I’m going to a shoot and I know that my hair has to be squeaky clean—because who knows what they’re going to do with it—I'll use the more traditional Stephen Knoll Shampoo and Conditioner, but for my normal life I'll use Wen. I feel like you do need anti-aging hair stuff because your hair is one of the things that changes [as you age], from the coloring to the texture."

Ashley Weatherford

"When I’m wearing it curly, I’ll wash it once a week but wet it several times throughout because it needs to be wet. Then sometimes I’ll wash with just a conditioner. I’ll use Cantu’s Leave-In Conditioner, which is so good for having your curls be bouncy without weighing them down. Then I also have the Devacurl Styling Cream in my shower, which I use immediately after washing on wet hair."

Anja Rubik

"It changes because of work, but I like to go a week in between washes. If I’m on vacation, even longer. I use Kerastase L'Incroyable Blowdry right after I get out of the shower at night on wet hair. It helps thicken the hair—then I wake up with something to work with.”

Grace Coddington

"I wash it about once a week because it’s very dry, and actually, it looks the best after two or three days usually. The waves come back. It looks the best if it just air dries, but I’m usually in a hurry and late, so I just blowdry it."

Loza Maléombho

"I wash my hair once a week. I use Pantene, but I also like Garnier Fructis. I use Queen Helene Cholesterol Hair Conditioning Cream as a conditioner—it’s in a little tub and it’s kind of paste-y and you use it for 15 minutes and then rinse it out. I blow dry it and then put aloe on the roots and shea butter in the ends."

Louise Follain

"It's washed every other day but it depends if I have something where my hair has to be really clean or not. I haven't found my perfect shampoo yet. I'm always in the supermarket looking for a new one because I don't have any favorites. But bad shampoos do make my hair look terrible, so you can’t just use anything."

Kim Kardashian

"For my hair, I don’t wash it every day. We start out with a blowout on day one, then we go into a messier vibe the next day, and then we flat iron it and do a really sleek look on day three since that requires a little oil in the hair. Day four could be a slicked-back ponytail, and on the fifth day is when you wash it. That’s a little excessive, maybe." [Laughs]

Melanie Huynh

"About once a week, I try to go to the hairdresser to have a blow dry. I hate washing it myself, so I’ll take my products to them. Otherwise I’ll do it myself with Orlando Pita Play Foam Volumizing Shampoo, which is new, and I’ll condition with the Play High Spirited Weightless Leave-In Conditioner. They’re really great for thin hair."

Noémie Lenoir

"My hair is a big deal. I never do color because I’m scared of drying it out. So yesterday I had a Kérastase mask on my hair all night long! My conditioner is Kérastase, and I try to shampoo once a week. But every morning I wet my hair and apply some conditioner. And I don’t brush with a brush, I put my fingers through it. When I dry, I put on a towel and leave it for like two minutes while I’m getting ready and that’s it."

Katherine Power

"Every morning I work out really early, 6AM at Tracy Anderson. Because it’s such a hot workout, I have to shower every single day, and wash my hair...typically I use either René Furterer Shampoo and Conditioner, or I have Jen Atkin's samples from Ouai that I’m obsessed with. And then I just started using an apple cider vinegar rinse, which I love. You can use it instead of shampoo and conditioner so that you don’t have to shampoo your hair every day. Every other day I’ll use it, and it’ll sud up and it cleans everything. I want to preserve my hair color longer, and I have a Brazilian blowout that I want to preserve, so I just tried it and I really liked it."

Sky Ferreira

"Amazon and I have become really good friends when it comes to finding stuff for my hair. Basically I put tons of shit in it and I don’t really know if it works. I can’t really wash my hair that often because it just dries it out. I wash it twice a week with Giovanni Tea Tree Shampoo, but just on my roots. On the ends I use Wen Sweet Almond Mint Cleansing Conditioner. I swear on my life it helped my hair grow. Then I have this Bumble and bumble Mending Masque so it doesn't get frizzy."

Amoy Pitters

"I use a lot of Réne Furterer products because they’re really moisturizing... [and] I wash my hair twice a week. Your scalp is part of your skin, so it should be clean to stimulate growth. Who wants to work with dirty, greasy hair?"

Catherine Deneuve

"Not being a natural blonde, I've always taken care of my hair. Christophe Robin has a Cleansing Purifying Scrub with Sea Salt that I use once every three weeks to clean the scalp. When I'm working, I only wash my hair twice a week because it's very thick and it will get too fluffy. But when I do wash it, I use the Christophe Robin Cleansing Mask with Lemon as a shampoo—it's really incredible for blond hair because it gives it so much shine."

Alicia Yoon

"For some reason, I’m one of the weird Asian girls born with very wavy hair. The shampoo and conditioner I use are Uka Wake Up and Uka Nighty Night—their haircare is amazing. When it’s really hot out, I’ll use this Tea Tree Purifying Shampoo from Aromatica because it’s clarifying but not super drying. Then, once a week, I’ll use a carbon dioxide deep-cleansing scalp treatment to take care of any buildup."

Kacy Hill

"I use this really cheap shampoo that I found, but it’s the best–it's called Renpure Argan Oil Shampoo and I bought it on accident. I wash my hair with it twice a week to preserve the color. And I love the It's A 10 Miracle Hair Mask. Back when I was modeling, I would use that a lot. You leave it on for a while, but when you take it off, your hair is perfect."

Sunny Shokrae

"My hair is thick, and it gets really crazy with humidity. I use Enjoy, which is this weird shampoo and conditioner brand that my mom introduced me to. [Laughs] It softens my hair, and it really locks and moisturizes. Every three days, I wash it, put coconut and argan oil in it, and then I let it air dry curly. After that, I'll straighten it on the first day so that it's more manageable and less knotty."

Aja King

"My hair routine is to let someone else do it. [Laughs] So much heat is being put on my hair, so I need to leave it alone when I can. It's challenging, though, because I have to wash my hair after I work out—and sometimes I work out every day. I use Pureology Shampoo and Conditioner, and after shampooing I'll put the conditioner on, go watch a movie, and wash it out later. When you have black girl hair, once we wash, we’ve gotta do the whole press and get in the edges and everything. That's a lot of heat to go back to straight on a daily basis."

—as told to ITG

Photos via ITG.

Next up: Your consummate guide to winter hair care for the season ahead.