The 401(k) decision boomers and Gen Xers regret the most

Retirement doesn't usually go off track because of one catastrophic decision. More often, it's the result of small choices that seemed harmless at the time, putting off savings another year, contributing just enough to get by, or assuming there would be plenty of time to catch up later. Those are the kinds of surprising retirement mistakes many older Americans now wish they could undo.

Recent surveys paint a remarkably clear picture. Boomers and Gen Xers tend to look back on the same handful of 401(k) decisions with regret, but they also point toward practical steps that can still improve retirement security. Here's what they wish they'd done differently.

Putting off retirement savings for too long

If there's one regret that comes up again and again, it's waiting to get started.

Nationwide's 2025 Protected Retirement survey found that more than 80% of Gen X and boomer retirement plan participants wish they had begun saving earlier.

Every year spent on the sidelines is one less year for investments to grow. Many millennials and Gen Z workers are starting a decade earlier, giving themselves a much longer runway.

Forgetting that time is just as valuable as money

Ask someone nearing retirement what they wish they had more of, and many won't say a bigger paycheck; they'll say more time.

CFP Board research found that nearly half of Gen X respondents estimate their financial mistakes have cost them at least $100,000 over their lifetimes, while 13% believe those missteps have cost them $500,000 or more. Many of those regrets centered on waiting too long to plan and save for retirement.

Those numbers aren't just about contributing more dollars. They also reflect years when money wasn't invested and therefore never had the opportunity to compound.

Not appreciating how compounding works

Compounding is easy to describe but harder to appreciate when retirement feels decades away.

More than three-quarters of boomers and Gen Xers surveyed by Nationwide said they wish they had understood it sooner. Even today, many still struggle with the concept. The survey found that 54% of Gen X and 39% of boomers misunderstood how compound growth works.

The gap matters because it's much easier to postpone saving when the long-term payoff doesn't feel real.

Spending years chasing growth without thinking about protection

Growing a retirement account is only half the challenge. Eventually, protecting those savings becomes just as important.

Northwestern Mutual found that half of Gen X respondents wish they had spent more time thinking about wealth preservation instead of focusing almost entirely on growth. Among boomers, 40% felt the same way.

As retirement gets closer, market swings have less time to recover. That's why many financial professionals gradually shift attention from maximizing returns to managing risk.

Waiting until retirement to think about retirement income

Many people spend decades learning how to save, but very little time learning how to spend those savings.

Nationwide found that more than 8 in 10 boomers and Gen Xers wish they had started earlier on strategies for protecting their portfolio from market volatility and creating dependable retirement income. Those conversations often involve taxes, withdrawal orders, Social Security timing, and investment allocation.

These are topics that generally benefit from years of planning instead of last-minute decisions.

Assuming a 401(k) pays a monthly check

This misconception catches many retirees off guard.

More than half of respondents believed their 401(k) would naturally provide a monthly income after they stopped working. 

In reality, most employer-sponsored retirement plans simply hold investments. It's up to the retiree to decide how much to withdraw, when to take it, and how to balance spending with the risk of running out of money.

Workers still have a valuable opportunity to catch up

For 2026, workers can contribute up to $24,500 to a 401(k). Anyone 50 or older may contribute another $8,000 through catch-up contributions, while workers ages 60 to 63 qualify for an even larger $11,250 super catch-up under SECURE 2.0.

Those higher limits won't erase years of delayed saving, but they could make a meaningful difference during peak earning years.

Retirement planning doesn't end when the paychecks stop

For people already retired (or a few years away), the biggest opportunity may be changing the goal.

The focus should shift from building the largest possible account balance to creating income that can support everyday spending through good markets and bad ones. That could include testing the portfolio against downturns and coordinating withdrawals across different account types.

Bottom line

The biggest 401(k) regrets are typically tied to waiting too long to save or postponing decisions that become more important with age. Whether you're still building savings or already drawing from them, now is a good time to check up on your retirement readiness and identify any gaps while there's still time to address them.

Don't overlook reviewing your beneficiaries and account allocations. Major life changes like marriage, divorce, or the birth of a child don't automatically update your retirement accounts. Taking an hour to review those details alongside your broader retirement plan can help ensure your savings are positioned to support the people and goals that matter most.