For 58% of Americans, a 401(k) is their only source of retirement savings, according to research from Charles Schwab. These workplace accounts are a good place to put away money for the future, especially since contributions are made with pre-tax funds and many employers match at least some of the money you put in. 

The problem is, most people aren't putting enough money into their 401(k)s. In fact, just over half of Americans responding to the Schwab survey were investing no more than 10% of their income. And unfortunately, the survey also showed most people are making a big mistake: They aren't increasing the amount they invest.

Fewer than half of investors had raised their 401(k) contributions in the past two years, and around a third of people who were automatically enrolled had never changed their contribution amount at all. 

Couple looking at financial paperwork in dismay.

Image source: Getty Images.

You should increase your 401(k) contribution regularly 

Unless you're already putting at least 15% to 20% of your income into your 401(k) and/or other retirement savings accounts, you should increase your contributions regularly.

It's a good idea to bump up the amount you're investing every time you get a raise because you can get closer to your savings target without having to change your lifestyle at all. Divert the increased income right from your paycheck before you get a chance to get used to having it, so upping your retirement savings amount becomes effortless. 

Even if you aren't getting raises, periodically increasing your contribution by a small amount is a good way to ensure you're prepared for the future. You probably won't miss a 1% decline in your income, but it can make a big difference if you add this extra money to your 401(k). And if you gradually bump up the amount you're contributing by about 1% of your salary or so every six months or once a year, you probably won't notice much of a change to your take-home pay.

Unfortunately, since the research shows less than half of Americans increased their contributions over two years, it's clear most people aren't taking advantage of these techniques. It also means most people haven't taken steps to rework their budget to find more money to invest, despite the fact their savings rate is well below what's recommended.

Make sure you're saving enough for the future

Whether you want to invest your raises in your 401(k), slowly inch up the amount you're contributing, or rework your budget to prioritize retirement investing, you should work toward saving more. 

Finding spare cash to invest might seem difficult, but a savings rate of less than 15%, including an employer match, is likely to leave you struggling. Now is the time to join the minority of Americans who've increased their 401(k) contribution recently. The longer you wait, the harder it will be.