Millions of seniors depend on Social Security to pay the bills, so much so that 59% of current retirees consider it a major retirement income source, according to the Employee Benefit Research Institute. But Social Security is facing a serious financial crisis that, if left unresolved, could leave future retirees in the lurch. In fact, you'll often hear talk that Social Security is on the verge of bankruptcy and that those benefits won't be around for much longer. And that's a scary prospect.

The good news, however, is that Social Security pretty much can't go broke. The reason? The program's main source of revenue is payroll taxes, so as long as we have a workforce, Social Security is guaranteed some amount of funding.

Pile of Social Security cards.

IMAGE SOURCE: GETTY IMAGES.

But that funding only goes so far in covering the cost of benefits. Right now, it's not the program's only source of income, since Social Security has the ability to tap its cash reserves, or trust funds, to pay benefits as needed.

Those trust funds, however, are set to run dry by 2035, and once that happens, Social Security might have to reduce the amount it pays in benefits. As of now, that reduction is looking like 20%, but that estimate could change over time. Therefore, while Social Security isn't going bankrupt, it is facing some grave financial shortcomings that could leave future retirees hurting.

Don't get burned by Social Security

Though you can expect to collect Social Security income in some form during retirement, whether you will get your full benefits is questionable. Keep in mind that the age at which you file for benefits will have an impact, too. If you file at any point before reaching full retirement age, you'll see an automatic reduction in your benefits. You can file as early as age 62, but full retirement age doesn't start until 66, 67, or somewhere in between, depending on your year of birth. In the most extreme reduction scenario -- filing at 62 with a full retirement age of 67 -- your benefits will get cut by 30%. That's in addition to whatever cuts result from Social Security's lack of funding down the line.

That's why you really can't rely too heavily on Social Security in retirement. Although those benefits will provide some income, they're only supposed to replace about 40% of the average worker's preretirement income, and that's without a reduction. But most seniors need double that amount, more or less, to live comfortably. If you save efficiently during your working years, though, you'll have less to worry about if your Social Security benefits come in lower than expected for one reason or another.

Imagine you have 30 years between now and retirement. Here's the amount of savings you might build, depending on how much you're able to sock away each month:

Monthly Savings

Total Accumulated Over 30 Years (Assumes a 7% Average Annual Return)

$200

$227,000

$300

$340,000

$400

$453,000

$500

$567,000

$600

$680,000

$700

$793,000

Keep in mind that the return above is a little bit below the stock market's average. With a 30-year savings window, loading up on stocks is a more-than-reasonable thing to do, in which case you might snag an average annual 7% return or higher.

If you have less time between now and retirement, you'll need to save more on an ongoing basis to compensate. The point, however, is that you can take steps to secure a nice income stream later in life.

Though Social Security is hardly on the verge of bankruptcy, future cuts in benefits are a real possibility. Rather than make the mistake of relying too heavily on those benefits in retirement, start setting money aside for the future today. This way, you'll have less to worry about if Social Security's finances take a turn for the worse.