Social Security Disability Insurance (SSDI) is like a type of insurance that helps people who have a disability and cannot work to get money. To be eligible for SSDI, you have to have paid Social Security taxes on a job for a certain number of years and have a medical condition that meets the Social Security Administration's definition of disability. The SSDI payments depend on how much money you made before your disability happened. People who receive SSDI also can get Medicare after two years.