Last month, I downsized my closet by about 75% and built a capsule wardrobe composed of 30 items.

The experience was liberating, economical, and a major space-saver — so much so that I'm selling my gratuitous clothing and sticking with the minimal wardrobe.

Perhaps the most rewarding aspect of the project was how much time and energy it saved each morning.

Choosing what to wear to work became infinitely easier, simply because I had so few clothes to choose from. It was also nice knowing that I couldn't really go wrong with my decision — after all, I filled my capsule with my favorite, highest-quality items.

What's more, by simplifying the "What do I wear today?" conundrum, I wasn't wasting energy on mundane decisions, which meant more mental energy (and greater productivity) for the rest of my day.

I'm not proposing anything revolutionary — if anything, I'm behind the curve.

There's a scientific reason some of the most successful people wear the same outfit day in and day out.

Think: Mark Zuckerberg and his signature gray tee-shirt, Barack Obama and his blue or gray suit, and John Paul DeJoria and his all-black ensemble. Wearing the same thing day in and day out helps them avoid what psychologists call decision fatigue.

"Making decisions uses the very same willpower that you use to say no to doughnuts, drugs, or illicit sex," Roy F. Baumeister, a psychologist who studies decision fatigue and a co-author of "Willpower: Rediscovering the Greatest Human Strength" told the New York Times.

"It's the same willpower that you use to be polite or to wait your turn or to drag yourself out of bed or to hold off going to the bathroom," Baumeister said. "Your ability to make the right investment or hiring decision may be reduced simply because you expended some of your willpower earlier when you held your tongue in response to someone's offensive remark or when you exerted yourself to get to the meeting on time."

Barack Obama and Mark Zuckerberg. REUTERS/Jim Young

As Obama told Vanity Fair in 2012, "You'll see I wear only gray or blue suits. 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."

Zuckerberg said something similar during a public Q&A session, when asked about wearing the same tee every day: "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 ... 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."

I'm not quite ready to make the leap from 30 items to a mere handful or single uniform — but the option is always there, with Obama, Zuckerberg, and science in its corner.