When it comes to money, many people aren't getting it right — especially professional football players, NFL linebacker Brandon Copeland told CNBC on Wednesday.
But there's one thing in particular that they are doing wrong: Trying to "keep up with the Joneses."
Players entering the National Football League "end up trying to do what other people are doing in the locker room," Copeland said on "Power Lunch. "
"That is the biggest mistake people make."
And it's not just an NFL problem — but something Americans in general are guilty of, added Copeland, who plays for the New York Jets.
He's now making it his mission to educate people on how to manage their money. This year, he is teaching a class at his alma mater, the University of Pennsylvania, an Ivy League school, on financial literacy.
It's something he thinks is severely lacking in today's educational system. According to a 2018 survey by the Council for Economic Education, only 17 states require high school students to take a personal finance class.
"We've practiced our multiplication tables. We've practiced cursive at some point in time. We've never practiced budgeting," said Copeland, a member of the CNBC Invest in You Financial Wellness Council.
"Yet, when you come out of college you are expected to know it right off the bat," he added. "A lot of this stuff kids don't know, don't understand because no one has ever sat down and talked to them about it."
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Copeland practices what he preaches. He saves about 90 percent of his income.
For others, he suggests aiming to save at least half of their salaries. But even that may not be feasible — which is understandable, he said.
"Some people, they can't live if they are saving 50% of their money," he said.
What they should do, however, is take stock of their financial situation. They can start off by calculating all of their expenses — from rent to cellphones to their Netflix account — and see where they can cut back.
They should also understand what they value and why in order to avoid making unnecessary purchases, and find strong mentors, he advises.
— CNBC's Stefanie Kratter contributed to this report.
Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.