Social Security benefits are a key component of most people's retirement plans, and some retirees depend on those monthly checks for the majority of their income. In fact, half of married couples rely on them for at least 50% of their retirement income, according to the Social Security Administration, and around 1 in 5 couples depends on that money for at least 90% of their income.

If the fate of your retirement hinges on Social Security benefits, it's wise to fully understand how the program works. But apparently, more than half of older adults have no idea what to expect when it comes to their monthly checks.

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Most older Americans are in the dark when it comes to their benefits

One of the most important Social Security factors to understand is how much you can expect to receive in benefits each month. However, 52% of U.S. adults age 45 to 59 have no clue what their future benefit amount may look like, according to a recent survey from investment management firm Schroders.

Knowing your estimated benefit amount is important for a couple of reasons. First, it can give you a realistic expectation of how much you can depend on Social Security. Your benefits aren't designed to be your only source of income, so if you're expecting your monthly checks to cover the majority of your future expenses, you could be in for a rude awakening.

Second, because you likely won't be able to rely on Social Security alone in retirement, having a good estimate of how much you'll be receiving can help determine how much you'll need to save on your own. If you're clueless as to what your future monthly checks will look like, it's next to impossible to establish an accurate savings goal. And if you're blindly socking money away hoping it'll be enough, you may be headed down a bleak financial path.

The good news is that it's easier than you may think to estimate your future benefit amount. By creating a mySocialSecurity account, you can get a sneak peek of what your future monthly checks will look like based on your real earnings. By taking the guesswork out of Social Security, you can create a much more accurate retirement plan.

Factors that can affect your benefit amount

Your benefit amount isn't set in stone, and there are a few factors to consider as you're creating your retirement plan.

First, know that your benefit may increase the longer you work. When determining how much you'll receive, the Social Security Administration takes an average of the 35 highest-earning years of your career and adjusts that number for inflation. So if you haven't worked a full 35 years yet, you'll have zeros added to your average, which will bring down your benefit. But if you work more than 35 years (or increase your income during those years), you could potentially earn bigger checks by boosting your overall earnings average.

Another factor that affects your checks is the age at which you begin claiming. You're allowed to file for benefits as early as age 62. But by claiming earlier than your full retirement age (which is age 66, 67, or somewhere in between), your benefits will be reduced by up to 30%. If you wait to claim until after that age, though, you'll receive bigger checks each month. Those with a full retirement age of 67, for example, can receive a 24% bonus on top of their full amount by waiting until age 70 to claim.

In most cases, these reductions or bonuses are permanent. The age you claim will affect your monthly benefit for the rest of your life, so take this decision seriously. If you expect to live a very long life or if you have next to nothing saved for retirement, delaying benefits to earn those bigger checks may be the best idea. Or if the opposite is true and you have a healthy nest egg or don't expect to spend decades in retirement, claiming early might be the ideal option. Just make sure there's some sort of strategy behind your choice.

Social Security benefits may be a significant part of your retirement, making it all the more important to understand how they are calculated and how much you're expected to receive to be better prepared going into retirement.