Some things seem to have been around so long that we just take them for granted. When it comes to Social Security, it seems we expect to get those checks but very few of us know exactly what we've got coming to us and when.

One finding of a recent survey into retirement attitudes by the Employee Benefit Research Institute was that only 18% of workers can correctly identify the age at which they'll be able to claim their full retirement benefits. That could mean a very unhappy realization for the half of workers who think they'll be eligible sooner than they actually will.

To avoid any rude surprises when you call up the Social Security Administration the day of your retirement party, here are the basics that every worker should keep in mind.

Retirement age
To be eligible for your full Social Security retirement benefits, you have to start claiming them when Social Security declares that you've reached your full retirement age. (Yes, the government picks this age for you, whether or not you want to quit your job the moment you turn 60.)

The government, like most of the rest of the world, used to assume you hit retirement age at 65. Almost a quarter century ago, that changed. Now lots and lots of people will have to wait until they're older than 65 to claim their full retirement benefits. The Social Security Administration has a handy chart, which shows anyone born after 1937 will have to hit an age between 65 and 67 to claim their full benefits. Take a look to find out exactly when you'll be deemed eligible for full retirement.

Partial benefits
That's not to say you can't retire sooner. No matter what the Social Security Administration deems your official retirement age, you can start receiving benefits at age 62. If you want to take your money and run, you should know that your monthly check won't be as large as if you had waited until full retirement age.

Like many things in the government, there's a formula to figure this out. The same chart that tells you your official retirement age can also tell you what to expect if you start drawing your money early. You're likely to receive the same total benefits over your lifetime if you start taking your checks sooner. Your monthly benefits get reduced to take into account the longer time span that you'll be receiving benefits.

Cash in hand
That all sounds great, but what does it mean for your income in retirement? Even though you may not remember, you've probably gotten a statement from the Social Security Administration telling you whether you've accumulated enough working credits to qualify for benefits. It will also tell you your expected payment if you collected your benefits early (at age 62) and your expected payments if you continue working until your full retirement age.

If you have a copy of that statement, it's worth taking a little time to make sure your earnings record is correct. You can match the reported earnings with your tax returns if you've kept copies of those records.

If you have no idea what I'm talking about, you can do one of two things. Request a statement from the government if you're sure you've never gotten one. It might be they have the wrong address on file. Or, you can use one of the government's online calculators to estimate the benefits you can expect to receive.

Once you've figured out what to expect, remember what not to expect -- Social Security was designed to be a safety net for retirement, not a program to ensure you'll live in the comfort and style to which you've become accustomed. To do that, you'll need to save on your own. If you need help learning how, give the Fool's Rule Your Retirement newsletter a try. You'll not only get great information on all the cumbersome details of the Social Security system, but you'll also find useful advice on how to put together the best retirement plan you can. Take a look today with our free trial.

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