Social Security will pay more than a trillion dollars in benefits to around 65 million Americans in 2020.

These benefits can be a lifeline, especially for retired or disabled Americans. Unfortunately, Social Security rules can be confusing, and many people end up missing out on income they should've received. You don't want to be one of them, so be sure you avoid these three big blunders that could come at a cost of more than $100,000. 

Older couple looking at computer in dismay.

Image source: Getty Images.

1. Claiming benefits at the wrong time

You have the choice of starting Social Security benefits as early as 62, or putting off claiming in order to raise the amount of your benefit. Waiting until your full retirement age ensures you won't be hit with early filing penalties, and delaying even longer allows you to raise your monthly income by earning delayed retirement credits until 70.

Unfortunately, making the wrong choice could be extremely costly.

Say you had the option to claim an $1,125 benefit at age 62 but decide to wait until 70 to max out your benefits -- and you sadly pass away a month before your 70th birthday. You'd have missed out on more than $106,875 in income based on the choice you made.

Obviously, you couldn't know up front that that would happen. And you just as easily could've lived well into your 90s and ended up with more lifetime income by waiting. Unfortunately,  since you can't tell how long you'll live, it's difficult to know what's best. But you should calculate your break even point and consider your likely longevity -- based on family and personal health history -- when deciding what claiming age is right for you. 

2. Divorcing before being married 10 years

If you don't have your own work history, you can claim benefits based on a spouse's work record. You'll also have the option of claiming spousal benefits if your husband or wife was a higher earner than you, although you can't get both your own benefit and your spousal benefits -- it's one or the other. 

Eligibility for spousal benefits doesn't necessarily end when your marriage does, either. You're still entitled to them as long as you were married for at least a decade. Unfortunately, if you're close to this threshold but end your marriage, you won't be eligible for any spousal benefits at all. 

Obviously, you don't want to stay in a bad marriage indefinitely just to protect your access to retirement income. But putting off signing the divorce papers for a little while could make a huge difference in your financial security -- especially if you aren't entitled to any Social Security benefits of your own. 

The average spousal benefit comes to $787. If you're retired for about 18 years and miss out on spousal benefits during that entire time, you could lose out on almost $170,000 in income you could've had.

3. Not understanding the benefits you're eligible for

Far too many people don't understand exactly what benefits they might be eligible for from Social Security, and this can be an extremely costly error.

In fact, a Simplywise study found 62% of people think divorced spouses aren't eligible to collect survivor benefits. This isn't the case. If you were married for at least 10 years and you didn't remarry before the age of 60 (or before age 50 if you're disabled), you should be eligible if your ex passes away. 

Survivor benefits can be even more valuable than spousal benefits. With survivors of deceased workers collecting an average monthly benefit of $1,220, you could miss out on more than $263,000 if you don't claim them, and would've been eligible to receive them over an 18-year retirement.  And, since you can also receive survivor benefits when you're younger than traditional retirement age if you're disabled or are raising a deceased spouse's children, your losses could be even more substantial. 

Even those who are entitled to their own Social Security checks could still miss out on tens of thousands of dollars in income if they don't understand the rules for survivor benefits. In fact, an Inspector General report identified more than 15,076 retirees lost an estimated $193.8 million by not claiming them.  

Unfortunately, these blunders are far too common and can happen to anyone who doesn't understand how Social Security works. Make sure you research all your options and take the time to make an informed choice so you can get the full amount of money you deserve.