Facebook CEO Mark Zuckerberg:

"I really want to clear my life to make it so that I have to make as few decisions as possible about anything except how to best serve this community," Zuckerberg said, after clarifying that he had "multiple same shirts."

"I'm in this really lucky position, where I get to wake up every day and help serve more than a billion people. And I feel like I'm not doing my job if I spend any of my energy on things that are silly or frivolous about my life," he said.

Steve Jobs’ the late Apple co-founder was best known for his visionary leadership and innovation—but he was also known for his unvarying signature look. Unlike most corporate executives, who wear suits and ties, Jobs was committed to his chosen uniform of a black mock turtleneck, blue jeans and New Balance sneakers.

Jobs wasn’t the first to go his own unusual yet unchanging way, and he certainly wasn’t the last. Others include Facebook CEO Mark Zuckerberg, fashion designer Michael Kors, Segway inventor Dean Kamen.

William Arruda, a personal branding guru and author of Ditch. Dare. Do!, says this practice can be part of personal branding. “They wear what they wear because that’s what they feel comfortable wearing,” he says. “When you wear something that just feels right, you are confident. And it is also great to have a trademark look. It makes you memorable and distinctive.”

Others do it to be more efficient.

Take Albert Einstein. It has been reported that the famous physicist bought several versions of the same grey suit because he didn’t want to waste brainpower on choosing an outfit each morning. Now—decades later—President Obama does the same.

Michael Lewis wrote in a recent Vanity Fair article:

You also need to remove from your life the day-to-day problems that absorb most people for meaningful parts of their day. “You’ll see I wear only gray or blue suits,” [Obama] said. “I’m trying to pare down decisions. I don’t want to make decisions about what I’m eating or wearing. Because I have too many other decisions to make.” He mentioned research that shows the simple act of making decisions degrades one’s ability to make further decisions.

“Famous business people and politicians are known to be consistent with their wardrobe because it’s their brand identity,” says Dan Schawbel, founder of Millennial Branding and author of Me 2.0. “It’s who they are, how they want to represent themselves and make a statement. It’s not about what you wear, but what you accomplish. [Mark] Zuckerberg, for instance, wears casual clothing because he represents the entire generation of young people who don’t want to wear suits to work.”