Meet a 71-year-old who retired as a radiologist and professor, and now runs a banana-skewer business: ‘I never want to retire. Why would you do that?’

At 71, Richard Brown feels like a college student once more. A former radiologist and professor, Brown formally retired in 2020 but quickly found another job and joined a health care startup. Now, he's become a product entrepreneur, which excites him more than ever. "My hobbies tend to be learning something new," he told Fortune. "I think I never want to retire. Why would you do that? You spent all this time learning something—and things get easier for you when you get older in some ways because you're a little bit wiser."

His latest project is Poka Snack, a skewer for easier banana freezing and eating. Launched on Kickstarter, it has raised over 90% of its $4,000 goal and amassed 14,000 TikTok followers. For Brown, it's more than a frozen skewer business; it's another chance to step out of his comfort zone, learn, and find the energy of starting over. As he puts it, "It's almost like being in college again. You have that adrenaline flowing. You want to accomplish something."

Brown, a nuclear medicine physician who became a professor at the University of Michigan in 2004, retired in 2020 but took a new job at the University of Utah's radiology department first as the first vice chair of clinical operations and later as the company's chief health strategy officer. Despite this constant change, he remains engaged, learning and growing with each new opportunity.

His philosophy on entrepreneurship emphasizes embracing risks and not being afraid of looking foolish. He launched several internet ventures while still practicing medicine and even created educational websites for cancer patients. Despite the dot-com bust, he learned not to let failure or fear of looking foolish hold him back.

Brown's Poka Snack idea came from his love for frozen bananas but dissatisfaction with existing products. After testing 40 prototypes, he settled on a design with a unique semi-helical geometry, which he's now producing with a U.S. manufacturer while finalizing packaging. His venture has also taught him about using AI throughout the entire product development process.

Brown emphasizes that instead of worrying about finding the perfect career path, one should focus on what genuinely interests them. He believes that never stopping learning or experimenting—and starting over when needed—is key to success.