Your monthly Social Security benefit is calculated based on your 35 highest-paid years of earnings, and you're entitled to it once you reach full retirement age, or FRA. FRA is based on the year you were born, as follows:

Data source: Social Security Administration.

However, you don't have to claim Social Security at your precise FRA. You can file sooner -- as early as age 62 -- in exchange for a reduced benefit, or you can wait to sign up past FRA and boost your benefits by 8% a year, up until age 70. Of course, the downside of going the latter route is clear -- you'll need to wait longer to get your money. But in spite of that, here are three really good reasons to delay your benefits as long as you can.

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1. You're guaranteed your boost

When you invest in stocks or other assets, there's risk involved, and you're not guaranteed to make money in the process. When you delay your Social Security benefits, your boost is guaranteed. When else in life will somebody promise you an 8% yearly return like that?

2. It'll motivate you to take care of your health

One interesting thing about Social Security is that it's designed to pay you the same total lifetime benefit regardless of when you initially file -- but only if you live an average lifespan. If you end up living longer than the average senior, you'll generally come away with a higher lifetime benefit by delaying your filing as long as possible. And that's why it pays to sign up for Social Security at age 70. If you do, you may be more motivated to take the best possible care of your health so you're able to snag more money from Social Security in the course of your retirement.

3. You can compensate for missing savings

Ideally, Social Security should only make up a portion of your retirement income, and the rest should come from other sources, like savings in an IRA or 401(k) plan. But if you've missed the boat on saving independently, a higher Social Security benefit is a good way to compensate. In fact, if you really have a minimal amount of savings and no pension or income from part-time work, you may need to delay your benefits and snag that boost or otherwise wind up on the brink of poverty later in life.

It really pays to wait

Waiting to collect a chunk of money that you're unquestionably entitled to isn't an easy thing to do. But delaying your Social Security filing as long as possible makes sense for a lot of reasons. If you can't hold off on claiming your benefits until age 70, your next best bet is to delay your filing by two years, or even one. But if you do manage to hold out as long as possible, you'll be doing your part to boost your financial security once your time in the workforce comes to a close.

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