For the Post-9/11 GI Bill, it depends on when you were discharged from active duty. If your service ended on or after January 1, 2013, your benefits will not expire thanks to a law called the Forever GI Bill–Harry W. Colmery Veterans Educational Assistance Act. If your service ended before January 1, 2013, your benefits will expire 15 years after your last separation date from active service. For The Montgomery GI Bill–Active Duty, you usually have 10 years to use your benefits, depending on your situation. For The Montgomery GI Bill–Selected Reserve, your eligibility usually ends the day you leave the Selected Reserve, but there are exceptions to this rule.