Social Security is the primary source of income for 49% of adults who have been retired for more than 10 years and 43% of recent retirees, according to a survey by Nationwide. Interestingly enough, that same study found that only 20% of adults nearing retirement believed they would be able to rely on Social Security as a primary income source -- and they have good reason to feel that way.

Social Security isn't going away, but it will be changing, and it probably won't cover as much in the future as it does today. Below, I explain how Social Security could change, how you can maximize your benefits, and other ways you can boost your retirement savings.

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Possible changes to Social Security

The trust funds that pay Social Security benefits are predicted to run out of cash reserves by 2034 unless changes are made to the program. No one knows yet what these changes will look like, but a few options have already been proposed, including:

• Reducing benefits.
• Raising the Social Security tax rate (currently 12.4%, split between employee and employer).
• Raising the amount of income subject to Social Security tax (capped at $128,400 in 2018).
• Raising the full retirement age (currently 66 or 67, depending on the year you were born).
• Reducing cost-of-living adjustments (COLAs), which help the value of Social Security keep pace with inflation.

This last possibility is of particular concern to retirees who rely on Social Security to provide the bulk of their retirement income. If COLAs are reduced, then the value of Social Security will decrease over time and retirees will have to dip into their personal savings to make up the difference. This could deplete their retirement accounts more quickly than they were anticipating, leaving them without enough money to cover their bills in the final years of their lives.

What to do if Social Security is your main source of income

If you're not already retired, you should take steps now to maximize your Social Security benefit so that it will go further. There are two ways you can do this: boost your income or delay claiming your benefits. Your Social Security benefit is based on your average monthly income during the 35 highest-earning years of your life. So anything you can do to increase your income now will raise this average and result in bigger checks.

Delaying Social Security beyond your full retirement age will also increase your benefit amount. This maxes out at age 70. If you wait until this age to claim benefits, you will get 124% or 132% of your scheduled amount, depending on if your full retirement age is 67 or 66, respectively. You can begin claiming Social Security as early as age 62, but your benefits will be reduced to as low as 70% or 75%, so this is not a good choice if you want to maximize your benefits.

In addition, you should make regular contributions to your personal retirement accounts. Not only will this give you greater financial security in retirement, but it will also give you a tax break now if you're using a 401(k) or traditional IRA. You're allowed to contribute up to $18,500 to a 401(k) and $5,500 to an IRA in 2018. Adults over 50 may contribute up to $24,500 to a 401(k) and $6,500 to an IRA.

Those already in retirement may have fewer options if the value of Social Security does decrease over time. You might have to look for ways to reduce your living expenses, like downsizing or staying home instead of traveling. You could also consider picking up a part-time job to get some more cash coming in. If you're not sure how to make your money last, it may be wise to turn to a financial advisor for specific guidance on your situation.

No one wants to run out of money in retirement, but the likely changes to Social Security in the future could make this a real possibility for the millions of Americans who depend on it as their primary income source. By planning for the possible changes and regularly reevaluating your retirement plan, you'll be able to better weather the ups and downs.