It depends on when you retire. The Social Security Administration determines your so-called "full retirement age," which is somewhere between 65 and 67 depending on when you were born. (Your Social Security annual statement includes your lucky date. Visit the ssa.gov Web site for more details.)

If you take early Social Security benefits (anytime between age 62 and your full retirement age), your payment is reduced by $1 for every $2 you earn above the annual limit.

For 2010, that limit is $14,160. The rules are more lenient starting in the year in which you reach full retirement age. Your payment is reduced by $1 in benefits for every $3 you earn above a different limit, but only for earnings before the month you reach your full retirement age. For example, if you reach full retirement age in 2010, the limit on your earnings for the months before is $37,680. (If you were born in 1944 or 1945, full retirement age is 66 years.)

Now the good news: Once you have passed full retirement age you can earn as much as you want with no impact on your Social Security payout.

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