Every self-made millionaire has a different story of how they attained their wealth. While there are countless ways to build up your bank account, each approach requires focus, goals, commitment, a little luck and smart moves.

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For Andrew Lokenauth, a finance expert who leverages his Wall Street background to educate his millions of followers seeking investing and personal finance advice through his newsletter, Be Fluent in Finance, he found a strategy that got him to the top. Today, he’s a successful entrepreneur who helps others increase their net worth, but he also lost a significant amount of money to financial mistakes that he estimates cost him a staggering $5 million in wealth.

“The worst part is that most were completely avoidable,” he said.

Lokenauth has impressively achieved multimillionaire status, but his path wasn’t easy — is it ever? He still has regrets, but reveals how he overcame his financial blunders and how others can avoid them in a candid interview with GOBankingRates.

Regret #1: Not Maxing Out My 401(k)

For employees with access to a 401(k), Lokenauth advises taking advantage of it and maxing it out.

“My biggest regret was not maxing out my 401(k) in my early 20s,” he said. “I was making good money — about $100,000 to $300,000 — but I only contributed enough to get the company match. I thought I was being smart by keeping cash for opportunities.”

The “rookie” mistake cost him $1 million to $1.5 million in compound growth, he estimates.

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Regret #2: Pulling Out of Investments Too Soon

Lokenauth used timing to work in his favor early on, but timing wasn’t on his side later when he misread the market and pulled out a large portion of his portfolio during a downturn — his second major regret.

“It was my failed attempt at timing the market,” he said. “I was thinking I could outsmart everyone else and missed the recovery completely. The thing is, I was convinced I had special insight into market patterns.”

That move cost him around $400,000 in lost gains.

Regret #3: Letting Great Real Estate Deals Slip By

Lokenauth’s third regret is not buying certain properties when he had the chance because he thought the asking price was too high.

“That same property’s worth four times more now,” he said. “Sometimes I drive by it just to torture myself.”

Despite these costly missteps, Lokenauth made some other smart moves that paid off in a big way.