A SEP for Exceptional Conditions allows individuals to enroll in Medicare outside of the Initial Enrollment Period or General Enrollment Period due to certain exceptional circumstances, such as a disability or end-stage renal disease. A SEP for working aged/disabled individuals allows individuals who are still working and receiving group health coverage from their employer or their spouse's employer to delay enrollment in Medicare Part A and Part B without penalty until they retire or lose their employer coverage. The main difference is that a SEP for Exceptional Conditions is based on specific exceptional circumstances, while a SEP for working aged/disabled individuals is based on employment status.