Billionaire Mark Cuban has always been careful with his money.
When he was younger, "I did things like having five roommates and living off of macaroni and cheese, and I was very, very frugal," he tells Money. "I had the worst possible car — those types of things."
Even after earning millions, and eventually billions, the entrepreneur has continued to play it safe: "I've lived in the same house for 18 years and still have the same cars."
When Cuban became a billionaire back in the late '90s, however, he did make one splurge purchase, and he still stands by it.
"Honestly, when I first really made a lot of money, I bought a plane," he says. "That was my all-time goal because the asset I value the most is time, and that bought me time. ... Other than the plane, which is a big splurge, I'm still a slob. Not all that much has changed."
John Paul DeJoria, who is worth an estimated $3.3 billion, also made the same investment. The co-founder of Paul Mitchell hair products and Patron Tequila owns three private jets.
"For him, time is a precious commodity and he'll do what he must to preserve it, even if it means spending millions of dollars on his own airplanes," writes Farnoosh Torabi, who shadowed DeJoria on the CNBC show "Follow the Leader."
"His jets allow him to conduct meetings on the go and around the country without wasting hours at the airport."
Self-made billionaire Tilman Fertitta, who bought a private jet at age 35, has a similar outlook on the value of time. "It's how I do everything I do, being able to leave when I want to leave, go home when I want to go home," the owner and CEO of Fertitta Entertainment tells CNBC Make It. "I could not cover near as much ground [without it]."
At the end of the day, "time is the one asset we simply don't own," Cuban writes for Men's Fitness. That's why a "brutally expensive" private plane that "saves me hours and hours" is completely worth the price, he says.
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