Everyone born in 1929 or later needs 40 Social Security credits (sometimes referred to as a "Quarter of coverage") to be eligible for retirement benefits. You can earn up to four credits per year, so you will need to work in at least 10 years to become eligible for retirement benefits. During your working years, earnings covered by Social Security are posted to your Social Security record, and you earn credits based on those earnings. Each year the amount of earnings needed for a credit rises as average earnings levels rise.
In 2008, you receive one credit for each $1,050 of earnings, up to the maximum of four credits per year. For 2007, you receive one credit for each $1000 of earnings. If you become disabled or die before age 62, the number of credits needed depends on your age at the time you die or become disabled. A minimum of 6 is required regardless of your age.