Participating in an employer-sponsored 401(k) plan is one of the simplest and most effective ways to build long-term retirement wealth. Setup is effortless: contributions are pulled automatically from each paycheck, making consistent saving practically hands-free.
Many employers sweeten the deal with a matching contribution, which is essentially free money deposited directly into your retirement account. Some matches follow a vesting schedule, so it is worth checking the rules for your specific plan. If your match is flexible, or if you are already fully vested, you have a valuable opportunity to amplify your savings at no additional out-of-pocket cost.
Even so, 401(k) plans come with real pitfalls. Savers who are not paying attention can unintentionally limit their growth, take on unnecessary risk, or leave significant money on the table. The IRS raised the employee contribution limit to $23,500 for 2025 and $24,500 for 2026, meaning there is more room to save than ever. But contributing is only part of the equation. If a 401(k) is a cornerstone of your retirement strategy, understanding the mistakes that can quietly derail your progress is just as important as funding the account in the first place.
Pitfall 1: Investing in Options That Don’t Match Your Long-Term Goals
A key limitation of many 401(k) plans is their restricted investment menu. You typically cannot buy individual stocks, which can mean being stuck with options that do not fully support your long-term objectives.
Broad market index funds are common and perfectly acceptable for retirement savings, but by design they track the market rather than outperform it. Target-date funds are also widely used and convenient, but they tend to shift toward more conservative allocations as the target year approaches. That conservatism can meaningfully limit growth for investors who could otherwise tolerate more risk and a longer time horizon.
If you want the ability to build positions in specific companies or design a more customized allocation, consider complementing your 401(k) with an IRA. IRAs offer similar tax advantages but far greater flexibility in choosing investments that align with your goals. Under SECURE 2.0, catch-up contributions for savers aged 60 to 63 can reach $11,250 per year, creating an even stronger incentive to maximize both account types if you are in that window.
Pitfall 2: Paying High Fees That Eat Into Returns
Fees can erode a 401(k) balance faster than most investors realize. According to the Investment Company Institute, the average expense ratio for equity mutual funds held in 401(k) plans was 0.26% in 2024, down sharply from 0.76% in 2000. That progress is good news, but fees on actively managed funds or smaller employer plans can still run considerably higher.
The stakes are higher than they may appear. The Department of Labor has illustrated that a 1% difference in annual fees can reduce a retirement account balance by 28% over a long career. Beyond investment costs, some employer-sponsored plans also pass along administrative charges that participants cannot control. Choosing lower-cost index funds helps limit fund-level expenses, but you have no say in employer-level administrative fees.
A 2021 Government Accountability Office survey found that 41% of workers were unaware they paid any 401(k) fees at all. Knowing your plan’s fee structure and minimizing unnecessary costs is essential, because fees compound just as powerfully as the returns they are silently offsetting.
Pitfall 3: Facing Penalties if You Need the Money Early
Withdraw funds from a 401(k) before age 59.5 and you will typically face a 10% early withdrawal penalty on top of ordinary income taxes. There is a notable exception under the “Rule of 55”: if you separate from your employer during the calendar year you turn 55 (or later), you can take penalty-free withdrawals from that specific plan. As of December 29, 2025, a new SECURE 2.0 exception also allows penalty-free withdrawals of up to $2,600 to purchase long-term care insurance for yourself or a spouse, an amount the IRS may adjust for inflation in future years.
Still, careers and life circumstances rarely follow the timeline we plan for. If early retirement, job loss, or health changes force you to access savings sooner than expected, strict 401(k) rules can limit your flexibility in ways that hurt at exactly the wrong moment. Keeping a portion of your long-term savings in a taxable brokerage account ensures you have accessible funds without triggering penalties, giving you a financial buffer that a 401(k) alone cannot provide.
Pitfall 4: Forgetting About an Old Employer’s 401(k)
With job changes becoming more frequent, workers are leaving old 401(k) accounts behind at a striking pace. As of July 2025, an estimated 31.9 million forgotten 401(k) accounts hold roughly $2.13 trillion in assets, according to research from Capitalize and the Center for Retirement Research. The average balance in a forgotten account has climbed to about $66,691. Poor oversight, suboptimal allocation, and excess fees can steadily erode those balances over time.
The solution is straightforward. When you leave an employer, roll your 401(k) into your new employer’s plan or into an IRA. Whenever possible, choose a direct rollover, which transfers funds straight from one account to another. An indirect rollover, where you receive a check and must redeposit it yourself, carries a higher risk of missing deadlines and triggering taxes or penalties. Workers who have lost track of old accounts can now use the Department of Labor’s Retirement Savings Lost and Found Database, launched in late 2024, to help locate plans associated with their Social Security number.
Pitfall 5: Setting It and Forgetting It
Automatic contributions make a 401(k) easy to maintain, but a hands-off approach can quietly limit long-term growth. Markets shift, asset allocations drift from their original targets, and your personal goals evolve over time.
A 2025 Dayforce report found that the average 401(k) savings rate slipped from 9.2% in 2024 to 8.9% in 2025, the first decline in three years, partly driven by workers reducing contributions when budgets tightened. That backdrop makes periodic review more valuable, not less. Checking your account a few times a year to confirm your portfolio still fits your risk tolerance and strategy keeps you on course. And when income rises, increasing your contribution rate is one of the most efficient ways to build wealth. Directing each annual raise into your 401(k) before you adjust your spending habits can accelerate your savings in a way that feels nearly painless.
Editor’s note: This article was updated to include current 2025 and 2026 IRS contribution limits (including SECURE 2.0 catch-up provisions for ages 60 to 63), Capitalize’s July 2025 data showing 31.9 million forgotten 401(k) accounts holding $2.13 trillion in assets, the DOL’s new Retirement Savings Lost and Found Database, the new 2025 long-term care insurance penalty exception, ICI fee data showing an average 0.26% equity fund expense ratio in 2024, and Dayforce’s 2025 finding that the average savings rate declined for the first time in three years.
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