A Money Guru Bet Big on a Very Long Life. Then He Got Cancer.

Most of us will live an amazingly long life and should not worry so much about dying young.

Those are the words of Jonathan Clements, 61, who wrote more than 1,000 personal finance columns for The Wall Street Journal between 1994 and 2015. Plan on living past 90 and save accordingly, he advised, when he wasn’t running marathons or riding bicycles.

In May, he saw a doctor about some balance issues. Two days later, he received a devastating cancer diagnosis. Scans revealed a golf-ball-size tumor on his lung, and the disease has spread to his brain, his liver and elsewhere.

Anything beyond 12 decent months would be a victory. “I’m definitely on the clock here,” he said as we sat at his kitchen table this week.

Asking Mr. Clements whether he wishes to take any of his advice back might seem like the height of callousness, but he doesn’t shy away from much. He has already turned his horrible luck into crisp prose, filled with bold-font takeaways on his website, humbledollar.com.

He regrets very little. I wanted to know why.

Mr. Clements once described himself as a professional nag. To devoted readers like me, however, who hung on every word and did what we were told, he was a patron saint of fiscal prudence. (He and I were also Wall Street Journal colleagues from 2002 to 2007, though I felt sheepish about my occasional incursions onto his journalistic turf and did not try to befriend him then.)

His longevity planning instructions to readers included three components: First, save as much as you reasonably can and do it as soon as possible, so that compound interest can work in your favor for a very long time. Second, avoid taking Social Security before age 70, so the larger payment from that age onward can help you if you hit your 90s.