An NFL player who teaches a UPenn class called \'Life 101\' says saving money isn\'t about how much you make - it\'s about how much you spend

NFL player Brandon Copeland knows a thing or two about saving money.

The New York Jets linebacker told Business Insider he saves almost all of his salary - according to Spotrac, his NFL salary is a reported $1.2 million.

That's not to mention his numerous side hustles, which include running his own real-estate company with his wife and teaching a financial-literacy class he nicknamed "Life 101" at his alma mater, The University of Pennsylvania, with Brian Peterson.

According to Copeland, saving money starts with tracking your expenses - how much you can save all comes down to how much you're spending.

"Keep income out of it as long as you can," he said. "For me personally, it's not about the income I make, it's about what I'm spending and what can be cut."

He continued: "I ask myself, 'Is this the lifestyle I really need to be living? Do I really need to spend $14.99 a month for Spotify without commercials?' You don't need to [involve] income to think of these things."

What one spends on depends on what they value, Copeland added. For him, that's experiences like taking a trip with his wife. He said he doesn't need certain things and resists upgrades, like driving a Corvette to training - he'd rather take the Ford Focus.

Regardless of income level, many millionaires and billionaires cut back on what they spend - it's what helps them build wealth, according to Sarah Stanley Fallaw, the director of research for the Affluent Market Institute and an author of "The Next Millionaire Next Door: Enduring Strategies for Building Wealth," in which she surveyed more than 600 millionaires in America.

She found that frugality - a commitment to saving, spending less, and sticking to a budget - is one of the characteristics most predictive of net worth.

"Spending above your means, spending instead of saving for retirement, spending in anticipation of becoming wealthy makes you a slave to the paycheck, even with a stellar level of income," she wrote.

Consider Richard Branson, who resists buying luxury items. Meanwhile, the famously frugal Warren Buffett still lives in the modest home in Omaha, Nebraska, that he bought for $276,700 in 1958 (in today's dollars). He's never upgraded to a smartphone, pays $18 for a haircut, and spends no more than $3.17 on his daily McDonald's breakfast.

And, like Copeland, Mark Zuckerberg and Jeff Bezos have shown a preference for affordable cars - Hondas, to be precise.