“A lot of people think you’re a new-age hippie,” said Mr. Jensen, who sold his four-bedroom, four-bathroom house, downsized to a more modest home and maxed-out retirement accounts while firing. “They can’t even wrap their minds around it.”

In retirement, Mr. Jensen and his wife and two daughters plan to live on roughly $40,000 a year generated from investments. Because his wife currently works, they have yet to draw on those accounts. But already, it’s a life rich on time but short on luxuries: Groceries are bought at Costco, car and home repairs are done by him.

“People always assume there’s an external circumstance: ‘Oh, you must have received an inheritance,’” Mr. Jensen said. “We’ve just chosen to live far below our means. That itself is a radical idea.”