Some people chose to delay their retirement past their Full Retirement Age. In that case you can increase your Social Security benefits in 2 ways. Each additional year you work, up to 70 years of age, adds additional earnings and credits to your Social Security earnings record. In addition, your benefits will be increased by a certain percentage if you delay retirement. Even if you decide to delay your retirement be sure to sign up for Medicare 3 months before you become 65.
Most people earn the maximum of four credits per year.
If you were born after 1929 you need 40 credits to be able to get retirement benefits. Your credit record allows for interruptions if you stop working. Once you resume working your credit record will add any new credits to the old ones you previously earned. The administrative costs are paid from the trust funds described above and are about one cent for every Social Security dollar collected. The amount that you earned, and the number of credits that you have amassed will also determine the amount of the Social Security check that you receive.