Social Security Disability is like an insurance program. A worker must have paid social security taxes in order to be “insured,” similar to paying premiums on a private insurance policy.

The Social Security Administration measures contributions in “quarters of coverage.” To be fully insured, a worker must have a quarter of coverage for every calendar year after age 21, up to the calendar year before becoming disabled.

For an applicant over 31 years, he or she must have 20 quarters of coverage out of 40 calendar quarters, prior to becoming disabled. Another approximate version of the rule is that an applicant is eligible if she has worked and paid Social Security taxes for 5 out of the past 10 years. The rule for applicants under age 31 is less restrictive.