Let's talk about Warren Buffett. He's 90 years old, and he's been the CEO and chairman of Berkshire Hathaway for more than 50 years.

It's probably fair to assume he'll never retire, as long as he stays healthy. He made that pretty clear last year. Same goes for vice chairman Charlie Munger, still going strong at age 98.

But that doesn't mean Buffett has never opined on when might be the right time to step down. And he's certainly given indications of when he thinks other people should retire--both his "all-star" managers, and ordinary humans like you or me.

I dug up quite a few instances of this as I've been reading all 500,000 words worth of Buffett's annual shareholder letters, as part of a project for my new e-book, Warren Buffett Predicts the Future. (You can download the preview edition for free.)

A few interesting examples:

  • In 1986, Buffett went on at length about someone who would not retire--Rose Blumkin, then 94, who was still working "seven days a week" at Nebraska Furniture Mart, a Berkshire acquisition. (His takeaway: "I've persuaded the Board to scrap our mandatory retirement-at-100 policy.")
  • Repeatedly, he marks the retirements of the leaders of Berkshire's subordinate companies, usually with glowing praise. Most of them retired when they were considerably younger than Buffett is now--for example, Ken Chace, who ran the textile business Buffett originally acquired, and who retired at 75.
  • He urges "the all-stars," meaning all of the managers of acquired companies, not to retire--but also to be sure to have identified (and let him know by confidential letter) who they think should take over their businesses if anything should happen to them. "These letters will be seen by no one but me unless I'm no longer CEO, in which case my successor will need the information," he wrote in the 2010 shareholder letter, adding: "Your note can be short, informal, handwritten, etc. Just mark it 'Personal for Warren.'" 

And, we should note how Buffett said he replied when he was once asked directly at Harvard Business School, in 1990, when he would have been about 60, when he planned to retire.

"Berkshire is my first love and one that will never fade," Buffett wrote, adding that he'd told the student who asked: "About five to 10 years after I die."

Obviously, that's a slightly hyperbolic metaphor. But I think it's worth examining in context the way that Buffett insists he likely won't retire, and how he seems genuinely to bemoan the retirements of his "all-stars."

He explains in one letter that he views his job as chairman as simply to a) treat his Berkshire operating managers well, b) stay out of their way, and c) "allocate the capital they generate."

And he added elsewhere that when they do retire, it's best to replace them with other well-known, long-haul candidates:

"Our directors believe that our future CEOs should come from internal candidates whom the Berkshire board has grown to know well. Our directors also believe that an incoming CEO should be relatively young, so that he or she can have a long run in the job.

Berkshire will operate best if its CEOs average well over 10 years at the helm. ... And they are not likely to retire at 65 either (or have you noticed?)."

Buffett is not without human empathy, of course. At one point--when he marked the retirement plans of both his long-time personal assistant and Berkshire's CFO in the same letter back in 1992--he professed to "understand and empathize with the decision...to retire when the calendar says it's time," even though he added that it's "not a step I wish to encourage. It's hard to teach a new dog old tricks."

So, if we had to sum up his advice on retirement for great leaders, I think it comes down to avoiding it as long as possible, assuming:

  • They're enjoying their work.
  • They're continuing to provide significant value.
  • And especially, if they don't have an obvious successor lined up and ready to take over.

All other things being equal, keep working and don't retire. It's what Buffett has done, and it's what I think he believes the greatest leaders among us should do, too.

Reminder: The preview edition of Warren Buffett Predicts the Future is available here, for free.