Social Security is such a vital program that most elderly beneficiaries get 50% or more of their retirement income from it, while 21% of married ones and 43% of unmarried ones get fully 90% or more of their income from it. Clearly, it's worth trying to get as much from Social Security as you can.

The more you know about how Social Security works, the more you'll be able to benefit from it, so here is a chart featuring the most important thing to know about it, along with some additional vital information.

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For Social Security benefits, timing matters

When it comes to starting to collect your Social Security retirement benefits, the age at which you do so makes a big difference in how big those checks will be. Start at your full retirement age, and you'll collect your full benefits. Start collecting earlier, and the checks will be smaller, while delaying starting will result in bigger checks. Just how much bigger or smaller? Well, you'll first need to know just what your full retirement age is.

The full retirement age for Social Security used to be 65 for everyone, but it has been increased for many of us. For those born in 1937 or earlier, it remains 65; for those born in 1960 or later, it's 67; and for those born between 1937 and 1960, it's somewhere in between. No matter when your full retirement age is, you can claim and start collecting your benefits as early as age 62 and as late as age 70. For every year beyond your full retirement age that you delay starting to receive benefits, you'll increase their value by about 8% -- until age 70. So delaying from age 67 to 70 can leave you with checks about 24% fatter. If your full retirement age is 67 and you start collecting benefits at age 62, they will be 30% smaller.

The table below shows the approximate percentage of your full benefits that you'll get if you start collecting at various ages. Note that many people have retirement ages between 66 and 67, such as 66 years and 8 months, so the table doesn't offer precise numbers for all. But it still gives a rough idea of the effect of waiting or being early.

Start Collecting at:

Full Retirement Age of 66 

Full Retirement Age of 67 

62

75%

70%

63

80%

75%

64

86.7%

80%

65

93.3%

86.7%

66

100%

93.3%

67

108%

100%

68

116%

108%

69

124%

116%

70

132%

124%

Source: Social Security Administration. 

It's a wash!

While the age at which you start collecting your benefits matters, it doesn't matter as much as you might think. That's because the program is designed so that total benefits received are about the same no matter when you start collecting, if you have an average life span. Checks that start arriving at age 62 will be considerably smaller, but you'll receive many more of them. So for most people, it's close to a wash.

The average monthly retirement benefit was recently $1,404. That amounts to close to $17,000 per year. If your earnings have been above average, you'll collect more than that -- but relatively few people collect more than $30,000, so don't expect Social Security to provide as much as you'd like. (There are more ways to get the most out of Social Security, though.)

Social Security might seem like a boring topic, but think of it as crucial cash arriving in your bank account every month for many years, and it can start to get more interesting.