When you're creeping toward retirement age with little to no savings, it can be tempting to lean on your Social Security benefits a little too heavily.

For those with average earnings, benefits are only designed to replace around 40% of your income. And yet half of baby boomers say they expect Social Security to be their primary source of income in retirement, a survey from American Advisors Group found -- while just 12% expect to depend on personal savings to make ends meet.

While relying on Social Security too much in retirement isn't ideal, if it's your only option, the best you can do is optimize your benefits as much as possible. However, the average household can potentially miss out on thousands of dollars in benefits by claiming Social Security at the wrong time.

Social Security card next to calculator and statement

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How a minor mistake could cost you major cash

You can claim Social Security benefits any time starting at age 62, but you won't receive the full amount you're theoretically entitled to until your full retirement age (FRA) -- which is either age 66, 67, or somewhere in between. Then if you delay benefits beyond your FRA (until age 70), you'll receive additional money on top of your full amount each month.

The age at which you claim may not seem like it makes a big difference, but depending on when you claim and how long you live, it could make a difference of over $100,000, a new study found.

Only around 4% of retirees make the most optimal decision about when to claim benefits, according to a study from United Income. While 70% of beneficiaries claim before age 64, only 6.5% actually come out ahead financially by doing so. In addition, 57% of retirees would build more wealth over their lifetime if they wait until age 70 to collect Social Security, yet only 4% claim at that age.

As a result, claiming benefits at the wrong time can result in as much as $3.4 trillion in potential lost wealth among all beneficiaries -- or around $111,000 per household.

How to decide when is the best time to claim

There's no one-size-fits-all answer for when is the best age to claim benefits; what's right for one person may not be right for the next. The truth is that it's impossible to know exactly what age is best to claim, but you can make an educated decision so you're making the best choice possible.

Two factors that can heavily influence your decision include your level of savings and your life expectancy.

If you have an abundance of savings, you may not necessarily need to optimize your benefits based on income. Rather, you can claim based on convenience and personal preference. For instance, if you have a solid nest egg that you expect to last through retirement, you may choose to retire and claim benefits at 62 so you can enjoy more time doing the things you love in retirement. Because you don't necessarily need the extra money you'd receive by waiting to claim, you might as well make the most of your benefits by claiming as soon as you can.

On the other hand, if you have little or no savings and expect Social Security to make up most (or all) of your retirement income, it may be wise to hold off on collecting benefits until age 70 so you're receiving more money each month.

The other key factor is life expectancy. If you have reason to believe you won't live past your late 70s or early 80s, it may make more sense to claim sooner rather than later so you can enjoy your money while you can. But Americans are living longer than ever (with a third of 65-year-olds today expected to live until at least age 90, the Social Security Administration estimates), so if you plan to spend several decades in retirement, waiting to claim benefits can be a good idea. By claiming later than your FRA, you'll receive that boost in benefits for the rest of your life -- which can go a long way in your old age when your personal savings may have run dry.

Of course, nobody can predict exactly how long they'll live. But if you take a good look at your health (and your family's health history), you can make a more educated and realistic decision about when to claim benefits so that you come out ahead financially.

Everyone wants to make the most of their money, but not everyone understands how the decisions they make impact their finances long-term. Determining when to claim Social Security benefits may not seem like a life-changing choice. But make the right decision, and it can increase your retirement income for life.