Many seniors can't pay their bills using Social Security income alone. That's why they need their own savings going into retirement.

But building a large nest egg isn't easy -- not when life's expenses get in the way. Still, there's one simple move workers can make to boost their savings and increase their chances of getting to retire comfortably. And last year, a lot of people missed that boat.

Letting free money fall by the wayside

Many workers with access to a 401(k) plan are privy to some sort of matching program. Employer matches can vary, and some are more generous than others. But ultimately, they all work the same way -- you put in a certain amount of money from your earnings, and your employer will give you a certain amount of extra money for doing your part.

Serious person at computer.

Image source: Getty Images.

Last year, two-thirds of 401(k) participants received their full employer match, according to Vanguard's How America Saves 2021 report. But that means that one-third of workers left free money on the table by not contributing enough to claim their match in full.

Now to be fair, last year, the pandemic upended a lot of people's finances, and so many workers had no choice but to put their retirement plan contributions on hold and focus instead on their near-term needs. That's not something to be ashamed of in any way.

That said, workers who are now in a stronger position to put money into retirement savings should aim to take advantage of their full employer matches. Doing so could make a huge difference in the long run.

Say your employer will give you $3,000 a year in your 401(k) if you contribute that amount yourself. If you snag a free $3,000 in that plan over 20 years, and during that time, your investments generate an average annual 8% return, which is a bit below the stock market's average, you'll wind up with about $137,000 in total savings based on your employer's contributions alone. That's a lot of free money to give up.

If you're not sure how much money you need to put into your 401(k) to claim your full match, talk to someone in your payroll or benefits department to get that information. Then, take a look at your budget and find ways to shift or cut back on expenses so you can put in enough money to snag your complete match.

Don't lose out

It's not every day that free money comes your way. But employer matching programs in 401(k)s offer a unique opportunity to get your hands on free money that could serve you well during your senior years.

Of course, your company may have a vesting program that requires you to remain employed for a certain period of time until you're entitled to your match in full. That, too, is something worth looking into.

You wouldn't want to leave your job three months before you're fully vested in your match and lose out on some or all of that money. But either way, claiming your full match starts with contributing enough from your own earnings to qualify for it, so it pays to examine your finances and find a way to make that happen.