As the average retirement age continues to rise, will passive income be the solution?

The average retirement age is 65 for men and 63 for women, based on the Center for Retirement Research at Boston College. That’s up from 63 and 60, respectively, in 2001.

Blame the moving target on increased life expectancies, the rising age for full benefits from Social Security, the cost of healthcare, or any number of other hurdles to life after work.

Meanwhile, investing to fund a retirement likely to last 15 to 20 years or more often predicts the need for a nest egg of $500,000 to more than $1 million, depending on your preretirement income. That can be a formidable goal for workers who start saving late, are battling inflation, or are struggling with significant wage gaps.

One investor believes we’re focusing on the wrong thing. Retirement should not be about a big number — but cash flow.

When Joseph Drups left the Air Force in 2014, he was searching for an entrepreneurial dream: passive income — the literal “check in the mail” income with little or no involvement. Instead, as he wrote on his Drups Investing website, he “traded his time for money” as a computer programmer, website developer, and digital marketer.

After three years of searching for a way “to break the chain between my time and my income,” he discovered small business investing. Not startups, but existing local businesses — even if they were barely profitable.

Drups is nowhere near retirement, but he thinks that investing in small businesses will lead to the recurring income that eludes so many traditional stock market investors.

Read more: What is the average retirement savings by age?

After his first online acquisition, Drups began adding one business after another, which produced only modest income. As he brought additional small companies into his operation, income grew, but it was anything but passive income.

“I was buying a job,” he said.

His earnings grew from a few hundred dollars a month to five figures of annual revenue. Still, the combined income wouldn’t be enough to retire on.

His goal is to scale his strategy with other investors, allowing the operation to hire managers and operators.

Sam Dogen, better known as The Financial Samurai, was an early advocate of the personal finance concept of FIRE (Financial Independence Retire Early) in 2009. He’s a master of passive income and provides proof of his success (and failure — we’ll get to that in a moment) by publishing spreadsheets detailing his income.

What does Dogen think of the Drups strategy?

“I mean, that’s a terrible passive income idea,” he told Yahoo Finance in an interview. “I’m 48 years old now. The older I get, the more I want to allocate my cash to 100% passive income investments. You know, stocks, bonds, for example, right?”

With rental properties in his 20s and 30s, if a tenant had something break, “‘OK, no problem. Let me fix it,'” Dogen said. A portfolio of businesses would create the same challenges. “I mean, the idea is interesting from a potential capital return point of view, but from a passive nature, no way.”

He says businesses such as vending machines, laundromats, and car washes may sound good, but are “too much work for too little return.”

Dogen combines income from savings, stocks and bonds, rental properties, and publishing royalties to produce a diversified passive income. However, successfully implementing the strategy over the long term can tempt even the most frugal.

“My family and I could have been set for life. Instead, due to my inability to beat back real estate FOMO, I blew up our passive income. And because our passive income is now much lower, we are no longer financially independent,” Dogen wrote on his website in June.

He sold a large portion of his investments to buy “a nicer home.”

“You know, I went from feeling wealthy to feeling house rich, cash poor. Literally living paycheck to paycheck and hoping like a tree wouldn’t fall on my roof,” Dogen added.

Whether your retirement strategy is to build an ample investment account for retirement, lean on business income, or manage an enterprise — or an all-of-the-above approach — you’ll want to refine your thinking about your target retirement age.

“People are terrible at forecasting their misery,” Dogen said. “In 10 years, are you going to be happy doing what you’re doing now? In 20 years, are you going to be happy doing what you are doing now? If you’re truly miserable, you had better have come up with a plan and save and invested enough to generate enough passive income to give you those options to break free.”

Some retirement planning tips include:

Dogen has one last tip:

“If the amount of money you’re saving and investing each month doesn’t hurt, you’re not saving enough.”

Read more: Fixed annuities vs. CDs: Which is better for your retirement savings?