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Mark Zuckerberg - The Facebook CEO is known for having a closet full of gray T-shirts and jeans, which he insists on wearing to work every day.

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Steve Jobs - The late Apple founder's go-to outfit consisted of a black mock turtle neck, blue jeans, and sneakers.

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Michael Kors - He may be one of the world's most celebrated fashion designers, but Michael Kors likes to keep it simple when it comes to his own wardrobe. Think lots of jeans, black T-shirts, and black jackets.

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Janelle Monáe - The Grammy-nominated singer has nearly always opted for black and white outfits over the years.

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Barack Obama - The former US President told Vanity Fair that he decided to choose between just two styles of suit—navy or gray—during his presidency because he had "too many other decisions to make."

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Giorgio Armani - Armani is the genius behind what are probably the sharpest suits in the world. But away from the red carpet he's usually seen in cashmere sweaters and navy slacks.

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Albert Einstein - One of humanity's greatest minds, Einstein was a fan of gray suits paired no socks and unkempt hair.

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Tom Ford - If you custom design perfectly tailored suits, would you want to wear anything else? Tom Ford doesn't.

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Hillary Clinton - During her campaign, the former First Lady would often go for colorful but simply cut tops and blazers, paired with black trousers.

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Karl Lagerfeld - Chanel's creative director basically wears the same outfit every day: black pant suits, white shirts and tie, sunglasses, and leather gloves.

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Christopher Nolan - The 'Interstellar' director wears a shirt, a button-up vest, and sharp black blazer on a daily basis.

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Tom Wolfe - Journalist Tom Wolfe allegedly wore an all-white suit every day since 1962.

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The Pope - The Pope's "uniform" is unique and is worn every day because...well, because he's the Pope.

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Arianna Huffington - Cofounder of 'The Huffington Post' (and now Thrive Global CEO) Arianna Huffington is a fierce advocate of repeating outfits and following the "work uniform" trend.

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Simon Cowell - Simon Cowell seems to have two sets of clothes—the casual T-shirt and jeans combo, and his formal black pant suit and white (unbuttoned) shirt.

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Angelina Jolie - Jolie always looks exquisite on the red carpet, but the actress dresses very casually when she's out and about—whether just taking a stroll with her kids or carrying out duties as UNHCR Goodwill Ambassador. Skinny pants, basic blouses, and black coat are her clothes of choice.

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Louis C.K. - Unless he is at a formal event, the comedian is often seen wearing a black T-shirt and casual jeans.

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Dean Kamen - The Segway creator was wearing a denim shirt and jeans combo before it was cool!

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Johnny Cash - The music legend was known as "The Man in Black" exactly because he wore nothing but black clothes.

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Elizabeth Holmes - Elizabeth Holmes, CEO of Theranos, has also adopted the black-turtlenecks-and-blazers work uniform.

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Pee-wee Herman - Actor Paul Reubens's character
Pee-wee Herman is known for always sporting a white shirt, gray suit, and red bow tie.

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Riccardo Tisci - It seems to be a rule among fashion designers that they should keep their outfits as minimalist as possible, and that's exactly what Burberry's Riccardo Tisci does. Black T-shirt, black trousers, and white sneakers work just fine for him.

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Jean Nouvel - French architect Jean Nouvel wears all-white outfits in the summer, and all-black for the rest of the year.

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Grace Coddington - The creative director of American Vogue is almost always seen wearing black.

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Fran Lebowitz - The American author has been a fan of black pant suits for years.

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Slash - Former Guns N' Roses' guitarist Slash won't let go of his sunglasses and top hat, regardless of the occasion.

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Kelly Cutrone -

The founder of fashion PR powerhouse People’s Revolution is too busy to make decisions about what she should wear, so she sticks to all-black outfits daily.

See also: Surprisingly frugal habits of the British royal family

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