Social Security provides a key financial lifeline for the majority of U.S. retirees, but it's not always easy to navigate all of its rules and requirements. With many obscure provisions that aren't easy to find, it can be easy to leave little-known benefits on the table unclaimed.

Once you know what Social Security benefits you're supposed to get, you can follow up and claim them. Below are three often-neglected provisions that many Social Security participants are surprised to discover.

A Social Security card embedded in a spread-out pile of U.S. currency.

Image source: Getty Images.

1. Benefits for ex-spouses

One of the most confusing set of rules in the Social Security world deals with divorced couples and Social Security benefits. In general, if you were married for 10 years or more and then divorced, then you can collect spousal or survivor benefits on an ex-spouse's work history. But if you cut the knot before hitting your 10th anniversary, then you're out of luck.

Where things get complicated is when it comes to remarriage. If your ex is still living, then ex-spousal benefits are only available if you haven't remarried. Note that you can still get benefits if you're single, even if your ex remarried. But there's an even bigger wrinkle here: If you remarry, but that subsequent marriage ends due to death or divorce, then you once again become eligible to claim benefits based on your first ex-spouse's work history.

If your ex has passed away, then survivor benefits have even more complicated rules. If you remarried before turning 60, then remarriage again takes away the right to survivor benefits on an ex's work history. But those who wait until 60 or older before remarrying don't lose their rights to survivor benefits. That can create some odd windfall opportunities, so make sure you know about them.

2. The lump-sum death benefit

Social Security's most attractive quality is that it makes monthly payments that in most cases extend for the rest of your lifetime. That ensures that even if your retirement savings run out, your Social Security benefits won't.

It's probably because of this that most people don't really think very much about one small lump-sum benefit that Social Security pays. Upon a person's death, Social Security makes a one-time payment of $255 if there's an eligible person to receive it. Surviving spouses are almost always eligible, and children can also receive the payment if the child gets Social Security benefits or qualifies for benefits due to the death of the parent. That's most often the case when the child is younger than 18 or still in high school, although disabled children of any age are typically eligible as well. Even though $255 isn't a huge amount, it's worth taking if you're eligible to get it.

3. Early survivor benefits that you can take independent of your own retirement benefit

Another benefit that comes up when a spouse passes away is the survivor benefit. Like regular retirement benefits, survivor benefits are monthly payments that can last the rest of your life. Unlike most benefits, however, you're allowed to claim survivor benefits without being deemed to have claimed your own retirement benefits at the same time, or vice versa. That makes for some interesting planning opportunities that in some cases let you get some money now and more later than you'd otherwise be able to get.

One feature of survivor benefits for spouses is that you're allowed to claim them as early as age 60, with an even younger 50-year-old limit if you're disabled. Social Security might not even be on your radar screen at that age, and if you're not aware of the survivor provisions, then you can inadvertently miss out on years of monthly payments.

Get what you deserve

Not all Social Security benefits are obvious, and it's up to you in most cases to make sure you get what's coming to you. By being aware of these three little-understood provisions, you'll make sure that you get all the benefits you deserve rather than missing out on substantial amounts of money for your retirement.

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