Many companies featured on Money advertise with us. Opinions are our own, but compensation and
in-depth research may determine where and how companies appear. Learn more about how we make money.

About 166 million Americans pay into Social Security, but not every worker will eventually collect. To qualify for Social Security retirement benefits, you need to have worked at least 10 years.

The best way to see where you stand is to access the government’s easy-to-use web site: As a starting point, you'll want to understand your full retirement age, which varies on when you were born: If that was before 1938, it’s 65 years old; from 1938 to 1942, it rises by two months each year; between 1943 and 1954, it's 66; from 1955 to 1959, it rises two months per year; and from 1960 on, the age is 67.

Although your full retirement age isn't necessarily when you should claim your benefits, finding your estimated monthly payment based on that age -- also on the Social Security website -- will help you make some decisions about when to claim.

The truth is that you can claim a benefit as early as age 62 -- but if you do so, your check will be permanently lower. For some people, the decision will lop off as much as 25% each year.

Now, if you urgently need income, claiming early is not a choice; it is essential for monthly cash flow. But if you don’t have to claim early, choosing to do so can be a bad idea, both for you and for your spouse. In fact, many experts believe that the single worst decision that seniors can make is to claim Social Security early. That’s because if your spouse plans to claim benefits based on your work record, he or she will also face a lifetime of lower benefits because you filed early.

While the system penalizes you for claiming early, it also rewards you for waiting beyond full retirement age. For every month you delay your claim, you’re entitled to Delayed Retirement Credits. These can yield up to 8% a year in additional benefits until they are maxed out, which happens at age 70.

Of course you'll have to do without the monthly income until you claim -- but provided you can wait, delaying can add up to big money later on.