Most U.S. workers don't contribute 90% or more of the maximum annual 401(k) contribution limit, nor do most invest at least 15% of their income in retirement accounts. However, a small number of Americans do. They're called "super savers" and representatives from the Principal Financial Group recently surveyed more than 1,700 of them between the ages of 20 and 54. 

These supersavers are setting themselves up for a secure future and it might do your own retirement plans some good to learn the tricks they're using to do it. In fact, here are four big sacrifices the Principal survey suggests they've made in 2020 to enable them to invest so much for retirement. 

Smiling woman putting money into piggy bank.

Image source: Getty Images.

1. Driving an older car

A whopping 48% of super savers opt for an older vehicle instead of upgrading so they can put more money into savings. It's not surprising this tops the list of sacrifices because a car payment can be one of the single biggest obstacles to saving.

Opting for an older car with a smaller car loan -- or no loan at all -- is also an easy lifestyle choice to sustain. Rather than giving up luxuries such as dining out or gym memberships, which you'll feel the loss of on an ongoing basis, you simply make one change and free up a ton of money every month. 

2. Owning a modest home

Forty-two percent of super savers own a home that's not overly expensive so they can contribute more to their retirement accounts.

This, too, is a lifestyle decision you make once rather than a continuing series of sacrifices. And with a growing number of retirees carrying a mortgage into retirement, it can pay off both by enabling more savings now and by making it easier to afford payments later or to pay off your home in full before leaving the workforce. 

3. Not traveling as often

Although COVID-19 has seriously limited Americans' ability to travel anyway, taking trips has long been a popular pastime and a big expense for many. However, 39% of super savers say they take fewer trips than they'd prefer so they can save more for retirement.

Skipping a few expensive vacation trips can free up thousands of dollars for retirement savings. It may give you enough cash to see the world in your later years when you don't need to worry about getting time off work or coming home to a long to-do list upon your return. 

4. DIYing instead of hiring household help

A total of 39% of super savers indicate they've forgone hiring a housekeeper while 38% said they DIY other household projects rather than hiring outside help.

And while it may be a pain to try to handle cleaning and basic repairs on your own, cutting your costs substantially with some sweat equity is well worth it in exchange for more financial freedom. 

Should you emulate the habits of super savers? 

These sacrifices may not be ones that make sense for you. You may, instead, decide to adopt some other common tactics of those who come close to maxing out 401(k) accounts such as working more or buying primarily secondhand goods instead of shopping for new purchases. And that's OK. 

But what you should aim to emulate is saving at least 15% of income or trying to get as close as possible to maxing out tax-advantaged retirement accounts. The old advice of saving 10% is no longer sufficient in today's day and age, with most experts projecting returns below historical averages even as life spans are getting longer. 

The last thing you want is to hit your senior years with too little money and end up being forced to sacrifice because of it. Instead, make the choice now on what lifestyle changes you're willing to make to save yourself from this fate. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.