Claiming Social Security Spousal Benefits? This Is the 1 Thing You Can't Afford to Get Wrong.

If you don't have much of a work history, you may be in line for a modest monthly Social Security benefit -- if you even qualify for benefits at all. But in that case, you may still have options. If you're married or an eligible divorcee, you may be entitled to receive spousal benefits from Social Security.

Spousal benefits can be a valuable source of retirement income. But there's one key claiming rule that tends to trip people up. And it's important to understand the nuances so you don't end up filing for spousal benefits at the wrong time.

Image source: Getty Images.

Understand what your spousal benefits are worth

A Social Security spousal benefit can be worth as much as 50% of your spouse's primary insurance amount, which is the benefit they qualify for at their full retirement age. If you claim your spousal benefit before reaching your own full retirement age, your monthly payments are permanently reduced.

However, once you reach full retirement age, you've already earned the maximum spousal benefit available. That's an important thing to know, because when you're claiming Social Security based on your own earnings record, you get to accumulate delayed retirement credits for waiting past full retirement age. Those credits are worth 8% per year you wait, until age 70.

But spousal benefits are not eligible for delayed retirement credits. If you're claiming spousal benefits, there's no sense in waiting beyond your full retirement age. If anything, waiting might result in a smaller lifetime paycheck for you.

In other words, if your spouse's primary insurance amount is $2,800, your maximum spousal benefit at full retirement is $1,400. Waiting to claim won't benefit you financially.

It's important to know the ins and outs

Social Security is a complex program, and the rules of spousal benefits differ from the rules of claiming benefits on your own wage record. You should also know that if you're eligible for Social Security based on your wage history and are also entitled to spousal benefits, you can't get both.

Rather, Social Security will pay you the larger of the two. So it's smart to run the numbers and figure out which benefit to claim. If you land on a spousal benefit, make sure to file at full retirement age to avoid losing out.

You should also know that spousal benefits, like regular retirement benefits, are eligible for a cost-of-living adjustment every year. So even though you can't boost spousal benefits by delaying, the monthly benefit you start out with is not necessarily the same amount you'll end up collecting for life.

The Motley Fool has a disclosure policy.