Being married in retirement has its perks. Not only does it give you someone to spend your days with, but it gives you someone to take care of you when you're ill or recovering from an injury. Plus, if you and your spouse are each bringing savings into retirement, that's two nest eggs you can pool and tap.

Being married in retirement can also be advantageous from a Social Security standpoint. That's because you may be eligible for spousal benefits from the program. This means that even if you never worked, you may be eligible for monthly income from Social Security regardless.

Not sure how those benefits work? Here are some key rules you should know.

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1. You can only collect up to 50% of your spouse's monthly Social Security payments

If your spouse is receiving Social Security and passes away before you do, you'll be entitled to survivors benefits from the program. And in that case, your monthly benefit will be equal to 100% of what your spouse received when they were alive, provided you wait until full retirement age (FRA) to claim it.

But spousal benefits work differently. With spousal benefits, the maximum amount you can receive from Social Security is 50% of what your spouse is entitled to each month. And again, that assumes that you don't sign up before FRA.

You should also know that if you're eligible for a monthly Social Security benefit based on an income record of your own, you may still be entitled to a monthly spousal benefit if it's higher than your personal benefit. But in that case, you'll only get the higher of the two amounts. You won't be able to receive two separate sets of benefits from Social Security.

2. You can't grow a spousal benefit by delaying your filing

If you're claiming Social Security based on your own earnings history, there's an upside to delaying your filing past FRA. For each year you do, up until the age of 70, your monthly benefit can grow 8%.

But those delayed retirement credits don't apply to spousal benefits. The most you can get is 50% of what your spouse collects, and there's zero financial incentive to hold off on claiming a spousal benefit beyond FRA.

3. You don't need to still be married to collect spousal benefits

The term "spousal benefits" might imply that you need to be part of a married couple in order to claim Social Security on somebody else's earnings record. But actually, people who are divorced are entitled to spousal benefits too, under the right circumstances.

To get spousal benefits as a divorcee, you'll need to have been married to the person whose record you're claiming benefits on for at least 10 years, and you can't be remarried.

The maximum spousal benefit you can receive if you're divorced is 50% of what your ex-spouse collects. And you don't necessarily have to wait for your former spouse to sign up for Social Security to get spousal benefits -- the rules are different from if you're currently married, in which case you do have to wait for your spouse to file.

Spousal benefits from Social Security can be a financial lifeline for seniors who aren't eligible for a monthly benefit of their own. Be sure to know how these benefits work so you're able to make the most of them.