Many people ask why social security disability benefits don’t begin on the date the judge found that they became disabled. Social security disability benefits never begin on the date one becomes disabled because of the waiting period of five full calendar months. Another rule limits payment of back benefits to 12 months before the date of the application. Therefore, your benefits begin either 12 months before the date of application or five full months after the date you were found to be disabled, whichever is later.