In 2009 Marcus Lemonis didn't have enough cash saved. He promised to never let that happen again

Talking money with Marcus Lemonis

Whether you're saving money or spending it, star of CNBC's "The Profit" and serial entrepreneur Marcus Lemonis has the same advice for you: Know your numbers.

"You have to understand what your needs are and what you can actually afford," Lemonis told CNBC.

The self-made millionaire sets rules for himself. He doesn't like racking up debt, and he ensures a portion of his paychecks goes to savings.

"When the 2008/2009 downturn happened, I didn't have enough cash saved, and I promised myself that I would always be prepared for potentially a recession again," he said.

Those money rules helped him achieve his long-term goal of buying a house. He said closing on his house was the most exciting thing he's done.

Lemonis is famous for his People/Process/Product principle, where he analyzes businesses on the quality of people, excellence and relevance of product, and the best way to deliver the product.

Tune into "The Profit" on Tuesdays at 10 p.m. Eastern.

Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.