Your oh-no moment could come minutes, months or years after you make a financial misstep.
Almost everyone has financial regrets, ranging from too high a spend on restaurant food to not investing in something that turned out to have a super high return.
Whether you got a late start on saving or you racked up credit card debt, you're not alone in making some ill-advised financial decisions.
One of the most common regrets is not saving enough or starting too late (or both), says Joe Wirbick, a certified financial planner and president of an advisory in Lancaster, Pennsylvania.
Most Americans don't start saving for their later years till they are in their early 50s, Wirbick says. But starting to save earlier means you can save in slower amounts.
A person who delays saving until age 30 would have to sock away $460 a month to save up $79,700 in 10 years, assuming a 7 percent return. Starting at 25, you'd need to save far less – $250 each month – to hit that same goal at age 40 .
"I find that using higher returns makes the example unbelievable, even though historical figures would say you should use 7.75 percent or 8 percent," he said.
Ashley Patrick, 34, regrets a 401(k) plan loan she and her husband took. The couple, who live in Charlotte, North Carolina, wanted money for a home remodeling project, and it seemed like a sensible strategy.
They were years from retirement. They had one child and were expecting a second, and they needed the extra space. Her husband's coworkers, who seemed financially savvy, said it was a perfectly reasonable option.
Things snowballed, and not in a good way.
The first problem: The couple didn't fully understand the loan. Patrick assumed it would use the 401(k) account as collateral – instead of an actual withdrawal. She was shocked to see that the account balance had dipped by $25,000.
Then, about a year into making payments, Patrick's husband was laid off – and informed he had 30 days to pay back the outstanding balance. That amounted to nearly $20,000, a large sum to have to suddenly come up with. They could not do it.
Since they did not repay the loan on time, the IRS counted it as income, boosting their bottom line on the following year's tax return. They wound up with an unexpectedly large tax bill.
The couple decided to put the remainder on a 0 percent interest balance transfer credit card. They threw all their muscle into paying it off in 18 months. "I didn't know a lot, till it all happened to me," Patrick said.
For people who find themselves also regretting a debt they took on, Patrick recommends paying it off as quickly as possible.
Silver lining: Patrick determined to educate herself about her finances, and today she blogs about her expertise on her own personal finance site, where she helps other people get a grip on their money.
Robert Bonardi, 38, says he is a diligent researcher. He is also a procrastinator. "I looked into investing years ago, but never pulled the trigger," he said.
Bonardi, who lives in the Charlotte area, found himself tripped up by the staggering number of options. He'd look into dividend-paying stocks, such as Coca Cola, and then not be able to write a check.
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"The incredible amount of options tripped me up," Bonardi said. "I would see an option, and I would look into it again, and find pros and cons."
Research led him to entirely different investment possibilities, and then he'd feel the need to do a deep dive into those investments. "It turns out, you can research forever if you really want to," Bonardi said. "I guess it's paralysis by analysis."
Silver lining: Bonardi says his choices were sound. He scouted gold when it was about $700 an ounce. Recently, the price was $1,291. "At least I know I am good at the research portion."
Once you're in trouble, it can be even harder to get out, says Chad Parks, founder and CEO of San Francisco-based Ubiquity Retirement + Savings.
Scrutinize your financial picture. "Then, begin to develop a plan for yourself to improve your financial health and reach your long-term goals," Parks said. "Determine your cash inflows and outflows, and create a realistic budget."
That gives you a baseline of your finances. Use online budgeting tools to help identify spending patterns or behaviors, so you can figure out some ways to save. Apps that help you track your finances are useful in helping monitor and improve money habits.
Next, set realistic goals. Parks recommends saving up a solid emergency fund. "Start thinking about what that means for you and open a savings account that you can automatically transfer money into monthly," he said. "Evaluate your debt and determine a realistic plan for paying it down."
Regret not saving? Start immediately, Parks says. "The cost of not saving earlier adds up drastically, so the sooner you can start, the better."
Disclosure: NBCUniversal and Comcast Ventures are investors in Acorns.