Most retirement plans are built on one big question: “What should I do?” But the more useful question might be: “What should I not do?”
This shift in perspective, known as inversion, has been a powerful tool for everyone from Nobel Prize winners to billionaire investors.
Physicist Richard Feynman used it while investigating the 1986 Challenger space shuttle explosion. While others focused on what should have worked, Feynman flipped the equation, asking what could have gone wrong and then tested it.
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That mindset led him to uncover the now-famous failure of the shuttle’s O-rings, rubber seals that lost flexibility in freezing temperatures.
Investor Charlie Munger later popularized the same mental model with his mantra: “Invert, always invert.”
His point? Rather than try to be brilliant, aim to avoid stupidity. Instead of chasing success, identify the ways you can fail and do the opposite. Essentially, problems often become clearer when viewed in reverse.
Applied to retirement, inversion means asking: What ruins a great retirement? And then plan to avoid it.
It’s a question worth asking. One survey found that 62% of retirees wish they could go back in time and change something about their retirement planning. While you can’t rewrite the past, you can look ahead and sidestep common mistakes.
This is the “rule of retirement inversion”: identify the threats, work backward from failure, and make smarter choices today to avoid regrets tomorrow.
So let’s flip the script and explore the ways people sabotage their retirement, and how to do the opposite.
The rule of retirement inversion helps you live your ideal lifestyle
Munger also once quipped, “All I want to know is where I’m going to die, so I’ll never go there.” That’s inversion thinking in action, which you can apply to where you retire.
According to AARP, 75% of adults over 50 want to age in place. Yet as an adviser and CFP®, Catherine Valega of Green Bee Advisory points out, many fail to plan for it.
“I see too many people having to make decisions in crises, instead of thoughtfully planning and preparing for how they’d like to live their golden years,” she says. “If you want to age in place, make renovations while you can still enjoy them.”
Even popular moves, like relocating for tax savings or better weather, can backfire. Kevin Brady, financial advisor and CFP® at Wealthspire Advisors, notes that people often relocate to states like Florida or Texas without trying them first.
“I always suggest renting for a few months to get a feel for daily life,” Brady says. “The tax savings may not outweigh being far from your community or family.”
Inversion can help here: picture yourself living in that future home, wherever it is, and consider what could go wrong. Planning around those risks now can spare you from major stress later.
But where you retire to may matter less than what you retire to. Many people work for decades dreaming of freedom, only to find themselves adrift once they have it.
“Retirement is a subtraction of structure, purpose, deadlines – even your inbox,” says Christopher Haigh, CEO and financial advisor at Iconoclastic Capital.
“That void doesn’t stay empty,” he says. “If you don’t fill it with intention, it gets filled with regret, resentment or unproductive habits.”
Research suggests that older adults with a strong sense of purpose report better health, fewer chronic conditions, and a lower risk of premature death.
That’s another area where using inversion can prove useful. Imagine what a loss of purpose and meaning in retirement might look like, then think of activities to help avoid it.
Inverting your retirement finances
You spend decades building wealth with one mindset: save. But in retirement, everything flips. Now, the challenge is to spend wisely. That shift can be harder than it sounds.
“Nobody really teaches you how to transition from accumulating money to using it,” says Melissa Caro, CFP® and founder of My Retirement Network.
“Most people don’t start paying real attention until their 50s, usually because they’ve stepped into a caregiving role,” she says. “That’s when the blind spots show up. Things you should have done earlier or at least understood.”
Haigh sees the same pattern. “Most people focus on hitting their number, but have no clue how to draw down assets efficiently. They end up living too conservatively in their early years, then face RMD bombs in their 70s,” he says.
Using inversion, instead of asking how much can I spend?, you can ask what could go wrong if I don’t plan my spending well? Do I spend too much? Do I miss out on some of my retirement dreams?
Experts suggest a simple planning method: review your cash flow each year. Estimate how much you’ll spend and where that money will come from, because retirement spending rarely follows a straight line.
A study from the Journal of Financial Planning reveals a common pattern known as the “Retirement Spending Smile.” Spending peaks early when you’re active, dips in the middle years, and rises again later on, due to health care needs.
Don’t be taken by surprise by health care costs
Health care is often one of the biggest surprises. Nearly 40% of retirees say their health and dental costs are higher than expected, according to EBRI’s 2025 Retirement Confidence Survey.
Many people assume that Medicare covers everything, but premiums, deductibles, and long-term care can add up quickly.
“I’ve seen retirees who nailed the investment side, but never understood how volatile healthcare expenses could be,” Haigh says.
“One couple had a Medicare Advantage plan that left them with thousands in uncovered rehab bills,” he says. “It wasn’t catastrophic, but it changed their travel and gifting plans for years.”
Another financial trap? Supporting adult children. One survey found that half of parents provide financial assistance to their grown children, averaging $1,474 per month.
“Everyone wants to help their kids,” says W. Michael Lofley, financial advisor and CFP® at HBKS Wealth Advisors. “But when that help becomes a pattern, it can quietly erode financial security. What starts as a gift or short-term loan turns into an ongoing obligation that was never factored into the plan.”
The lesson from inversion: Don’t just plan for what you want to spend. Identify what could derail your finances, and structure around it.
Rethinking your legacy
Most Americans don’t have a will, a sign that many would rather not imagine a world without them in it. But when you don’t prepare, it’s not you who suffers. It’s the people you leave behind.
“Without a plan,” cautions Patti Black, financial advisor and CFP® at Savant Wealth Management, “your kids are left guessing where the documents are, what your wishes were, who your advisors are. And guessing is the heaviest burden of all.”
Even if you have a will, it doesn’t mean everything’s covered.
“Not updating beneficiaries is one of the most common and costly mistakes I see,” says Caro. “People assume it’s just a formality. It’s not. If your listed beneficiary passes away and you don’t update it, the payout won’t go directly to your heirs. It could be tied up in probate and red tape for months.”
With the rule of retirement inversion, instead of assuming everything will work out, imagine the opposite: your assets not transferring, your wishes unclear, your loved ones confused and unprepared.
Perhaps, what we most often fail to invert is time.
“People overestimate how long they can wait,” Caro says. “They think, ‘I’ll deal with it when I’m older.’ But life doesn’t always give you the runway you expect. Health issues, cognitive decline, sudden loss, these things don’t wait. Planning early isn’t pessimism. It’s just smart.”
Sometimes the smartest move isn’t figuring out what to do right, it’s spotting what could go wrong, and fixing it before it’s too late.