When it comes to saving for retirement, too many employees are walking away from free money, and it’s costing them.

The rise of 401(k) plans has shifted the responsibility of saving for retirement to workers, and some aren’t taking full advantage of employer-sponsored plans, and that means leaving money on the table.

Employers may contribute a dollar for each dollar you save, commonly up to 6% of your total salary. “That a gift,” says Amy Reynolds, a partner in Mercer's retirement business.

But according to a recent TIAA-CREF survey, only 77% of employees who participate in an employer-sponsored retirement plan contribute enough to receive the full employer match. For employees earning less than $35,000 a year, only 64% receive the full match.

“Missing the match by just a percentage point or two can make a big difference in your total savings,” warns Dan Keady, senior director of financial planning at TIAA-CREF.

Finding Pretax Money

People tend to have a short-term mindset, says Reynolds when it comes to contributing, and don’t realize there are tradeoffs: $5 on another cup of coffee or $5 into savings.

Sometimes employees get the match, but stay on autopilot, and never increase their contributions as they continue on and receive raises. But here’s the most common reason, according Keady: They had other needs for the money.

Stagnant wages in the years following the Great Recession have put a financial strain on many households, which is why many experts recommend workers take a more approachable method to saving. People can start very small, perhaps $25 a paycheck, explains Keady.  “Then savings diligence over the years will make an enormous difference in retirement.”

It sounds simple, but, can be daunting, admits Keady. You think, “I’m contributing 5% now, I can’t go to 15%.” That may be right, he says, but you can go to 6%.

Although compound interest can turn even a relatively small amount of principal into a very large sum over a protracted period of time, many Americans don’t know what they’re missing, says Keady. For example, a 35-year-old worker making $50,000 per year with an employer contribution match of up to 3% that contributes enough to get the match, even if his pay remained flat for the next 30 years, with a 3% annual investment return, the matching funds alone would be worth about $72, 500 at 65.

Keady recommends spending just 15 minutes on an online calculator to see in real time how minor changes of even 1% can make a big difference.  “It’s like eating a little less and spending a little more time on the treadmill. Slowly the pounds begin to fall off.”

Rebalance and Pay Attention to Inflation

It’s also vital to keep an eye on the portfolio and have target dates to rebalance allocations, say, on a birthday, suggests Keady. “Even with a match but without a plan to rebalance, you can lose control of your portfolio.”

Investment allocations must be age appropriate relative to risk and investment timeframe, adds Reynolds.

And though inflation may be hard to predict, it’s an essential consideration to retirement investing. “When it’s low, people tend to forget about it,” says Keady, “but you need to be wary. A 1%, 2% or 3% rate of inflation doesn’t sound like much, but over a 20-year period it can have a huge impact on your retirement money.”

Never Too Late

While starting young and saving throughout a career is optimal, it’s never too late to play catch up, or at the very least recoup some savings, says Keady. For those older than 50, they can save as much as $23,000 in catch up contributions yearly. Those with the cash, can consider contributing $17,500, the annual allowable limit for 2014 and putting any additional savings (e.g., $5,500) into an IRA.

There’s also the choice to delay retirement. This may enable workers to push back the age at which they start drawing from Social Security, says Keady. However, planning to never retire isn’t a realistic savings strategy. “Health issues can derail that plan.”

Looking Backwards

Studies have shown that people are more inclined to save when they visualize themselves at the age of their parents or grandparents, explains Reynolds. “We need to ask ‘What am I going to look like at that point and what can I do now to improve my future?’”

Also, avoid looking at your 401(k) contribution as “just a number,” cautions Keady, “It’s your lifestyle and can make the difference between achieving or failing to get what you want for yourself in retirement.”