Shark Tank star and money expert Kevin O’Leary is famous for his honesty, his smart business decisions and, of course, his high net worth, which is currently estimated to be around $400 million. To be blunt, he is someone who knows much more than a thing or two about getting — and staying — rich.

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So, when someone like O’Leary advises you about finances, it’s worth your time to listen. As such, here are two pieces of money advice from O’Leary that, while potentially controversial to some, could help you if you’re looking to build wealth.

O’Leary is a strong advocate of always paying off your credit card balance in full each month. He has asserted that letting interest accrue over time is essentially throwing your money away (which is true). Not only can paying off your credit card bill each month help you stop getting dinged with high interest, but it is also the fastest way to boost your credit score.

However, transferring your balance to a credit card with a 0% introductory interest rate allows you to defer interest payments and gives you more time to pay off that balance without worrying about going into debt. This can be a smart move if you know you’ll have the money to pay your balance off soon, but you just need a little more time.

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You might feel compelled to combine all your finances once you get hitched. It’s easy for your emotions to take over, but be careful before you make this decision. O’Leary explained that maintaining separate bank accounts, investment accounts and credit cards is crucial even if you’re married.

In the event of a breakup or a divorce, untangling your finances can be a huge mess and may leave you high and dry. However, if combining your finances increases your collective financial standing or results in financial benefits such as easier money management and total visibility, only then might it be worth considering.

The bottom line is building a fortune like Kevin O’Leary’s takes more than a few bold financial moves. His wealth stems from various entrepreneurial ventures, most notably co-founding SoftKey Software Products, which evolved into The Learning Company and was later sold to Mattel for $4.2 billion.