When you see Kevin O'Leary, he's usually wearing something of a uniform: A black suit, white shirt and a black tie. Just watch an episode of ABC's "Shark Tank," where O'Leary is an investor — his look never changes.
It's a strategy.
"I looked at my closet one day, full of crap I don't wear," O'Leary tells CNBC Make It. "Piles of clothes, and suits and sweaters and shirts."
Instead of accumulating extraneous pieces of clothing he didn't love to wear, O'Leary decided to stick to 20 black suits, paired with 20 black ties and 20 white shirts.
"All my suits and shirts are hand made by tailors, I don't buy off the rack," O'Leary says.
"I invest in looking great all the time, and the way I do it is [paying for] great clothing, great shoes and a haircut every 10 days," he explains.
But there is one piece of clothing for which O'Leary was willing to break out of his pattern and spend a pretty penny on: a denim jacket from Yves Saint Laurent, which he tracked down and bought from an acquaintance for $2,800, he says.
"You can buy a jean jacket for $14, and it's going to fall apart on you," O'Leary says. "I had five of them I was never wearing. I thought, 'This is really terrible.'"
Instead, O'Leary decided to splurge and buy one expensive jacket. He thought the YSL jacket was "just perfect," he says. "I have exactly what I want, and I'm going to have it for the rest of my life. It's going to last forever."
Thinking of clothing as investment that makes you look and feel good is a lesson O'Leary learned from his mother.
"My mother loved Coco Chanel," O'Leary says. "The jackets cost a fortune. She would spend a year saving for one and then buy one jacket. Forty-five years later, after she died, the women in my family fought like cats and dogs to get near her clothing. Every piece was a classic."
(Indeed — previously owned Chanel jackets retail for thousands of dollars on vintage marketplace 1stdibs.com.)
But if you're going to buy expensive fashion, you have to be thoughtful about it.
"The number one place people spend a lot of money they shouldn't is on fashion," O'Leary says. "I'm always trying to get people to save at least 10 percent of their paycheck, and you can't do that if you're wasting it on the next shoe that drops, or the next sweater you want, or something that caught your eye when you're shopping."
Instead, says O'leary, "If you're going to buy a piece of clothing, get something absolutely spectacular," he explains. "Spend a whole lot of time researching it, find a designer you absolutely fall in love with, and start saving for it now."
Don't miss: Kevin O'Leary shares his No. 1 trick for tipping at a restaurant
Like this story? Like CNBC Make It on Facebook!
Disclaimer: CNBC owns the exclusive off-network cable rights to "Shark Tank."