The income you get from Social Security could spell the difference between covering your expenses in retirement and falling short. As such, you really can't afford to botch your filing or mismanage your benefits years before you're entitled to them. But if you fall victim to these four common mistakes, you'll risk hurting financially for years as a senior.

1. Not knowing your full retirement age

You're entitled to your full monthly Social Security benefit based on your work history at full retirement age, or FRA. Here's what FRA looks like, based on when you were born:

Year of Birth

Full Retirement Age




66 and 2 months


66 and 4 months


66 and 6 months


66 and 8 months


66 and 10 months

1960 or later


Data source: Social Security Administration.

If you claim benefits before FRA, you'll reduce them on a permanent basis. But in a Fidelity survey released a couple of years back, only 26% of Americans could identify their FRA. It's important to memorize your FRA, and to understand the consequences of claiming Social Security early -- namely, potentially slashing your monthly benefit by up to 30% for life.

Older man with serious expression

Image source: Getty Images.

2. Not understanding what goes into your benefits calculation

Your monthly Social Security benefit isn't a random number; it's a function of your average monthly wage, adjusted for inflation, over the course of your 35 highest-paid years in the workforce. Here's what that means: If you don't work a full 35 years, you'll have a $0 amount factored into your personal benefits equation for every year you're missing an income, leaving you with less each month in retirement. If you're missing some years of income within that 35-year time frame, it could pay to extend your career to replace some of those $0 figures with an actual salary to raise your monthly benefit.

3. Not checking your yearly earnings statements

Each year, the Social Security Administration (SSA) issues you an earnings statement. It has two purposes: to summarize your taxable wages for the year, and to estimate your monthly retirement benefit so you get a sense of what Social Security might pay you in the future. But if you don't check that earnings statement, you'll lose out in two regards.

First, you never know when that statement might contain an error that works against you, such as showing a lower amount of income for you than what you actually earned. If that's the case, correcting that error could help you avoid a lower benefit. But if you don't check that statement, you won't know to take action.

Second, not seeing that estimate of your monthly benefit could throw your retirement planning off course, so it's smart to get a sense of how much money you're entitled to. Granted, the younger you are, the less accurate that benefits estimate will be, but it's still good to know.

If you're 60 or older, you'll get your annual earnings statement in the mail. Otherwise, you can create an account on the SSA's website and access it there.

4. Not recognizing Social Security's limited buying power

Many people assume that Social Security will pay all of their bills in retirement. In reality, those benefits will only replace about 40% of your former income if you're an average earner, and most seniors need about twice that to maintain a comfortable lifestyle. So you shouldn't rely on Social Security too heavily, but supplement those benefits instead with savings of your own.

The more you know about Social Security, the less likely you'll be to file at the wrong time or make another mistake that hurts you financially. Read up on how the program works -- especially if retirement isn't so far away.