Living a long time is obviously something to aspire to. But when most Americans consider their potential longevity, they're faced with a nagging concern: What happens if they last longer than their money?

This is actually a pretty big worry for many of us, with respondents to a recent survey by the financial services company Northwestern Mutual indicating that, on average, there's a 45% chance they'll outlive their savings. Yet despite fears about ending up a broke senior, 41% of respondents said they haven't taken any steps to address this concern.

There's a very real chance many people won't have enough money to support them through their later years -- especially as the same survey found 22% of Americans have under $5,000 saved for retirement and 15% have nothing saved at all. 

If you're one of the millions worried your savings aren't sufficient, there are some steps you can take right now to try to make sure you have enough money to last.

Binder labeled "retirement savings plan" with calculator and glasses sitting on it.

Image source: Getty Images.

Raise your savings rate if you're still working

If you're still working, you're in the best possible position to make sure you don't run out of money in retirement. That's because you still have time to increase your contributions to your retirement savings account

While the traditional rule was that you should save around 10% of monthly income, this isn't really enough. Most people start saving too late to create a large enough nest egg if they put aside only 10% of income. And other factors -- such as more conservative estimates for investment returns, rising healthcare costs, and longer life spans -- also point to a need to save more than 10% of earnings.

If you don't want to worry that you'll outlive your savings, aim to save 20% of income for retirement. This is a lot of money, but would you rather sacrifice now or be left without funds when you're too old or sick to work?

You'll probably have to work up to saving 20% of what you earn. Some of the steps you can take to get there include:

  • Living on a budget that prioritizes saving for retirement.
  • Diverting money from raises directly into your retirement accounts before you get a chance to spend the money.
  • Gradually increasing automatic contributions.

If you're contributing 10% of income today, move up to 12% and see if you can live on what's left over -- then keep inching up the contributions over time, and you may not notice much of a difference in your day-to-day life. 

Know how much you can safely withdraw from your retirement accounts

How long your savings last depends on two big factors: How much you've saved and how quickly you take money out of your accounts.

One common rule of thumb, called the 4% rule, says you can withdraw 4% of your account balance in your first year of retirement and then increase your withdrawal rate to allow for inflation each year. So, a retiree with a $1 million portfolio could take out $40,000 in year one.  

Unfortunately, following the 4% rule isn't likely to make your savings last in today's world when returns are projected to be lower than in the past. The 4% rule also doesn't respond to changes in your investment portfolio's value if investments don't perform as expected. Instead, you should consider other approaches to determining a safe withdrawal rate

The safest approach is to only take out investment gains and leave your principal balance alone. Unfortunately, this approach won't work for many people because they simply don't have enough gains to provide a reasonable income without withdrawing at least some invested funds. 

Another option is to use Required Minimum Distribution tables from the IRS to determine the amount to withdraw. These tables tell you the minimum you must withdraw from a 401(K) or IRA starting at age 70 1/2 to avoid tax penalties. But you can also use them sooner -- the Center for Retirement Research at Boston College has used data from them to suggest safe withdrawal rates starting at 65. 

By making certain you don't withdraw more than is safe, you can hopefully ensure your savings last until the end of your life. 

Look for ways to cut costs as a senior

When you're already in retirement, your best option to make your savings last is to withdrawal as little as you can from your investment accounts.

While you don't want to compromise your quality of life, making some big changes could be necessary to reduce the withdrawal rate by enough if you're worried you'll outlast your savings. And making those changes ASAP is important so you don't take out too much money too early, making it even harder for your savings to last. 

Moving to an area with a lower cost of living, downsizing to a cheaper home, and switching from a two-car to a one-car household could all make a big difference in the amount you need to live on. 

You can take action today to make sure you don't outlive your savings

Whether you're already a senior or are still working and saving for retirement, you don't have to just accept the possibility you're going to outlive your savings.

You can make concrete changes to ensure your money lasts longer. The key is to act as soon as you know you'll have a shortfall, because the longer you wait, the less savings you'll have.