Security clearances, and clearance level, are granted based on Primary Military Occupationally Specialty (PMOS) and billet requirements. Finances, convictions, OCONUS travel, and other circumstances may have an effect on a Marines ability to sustain their appropriate clearance levels. Clearance levels must be maintained in order to effectively work in your PMOS and to remain eligible for retention in accordance with NAVMC 1200.1F (MOS Manual).
To maintain any of the three levels of clearance eligibility - Periodic Re-Investigations are required at a minimum:
Top Secret – every 5 years
Secret – every 10 years
Confidential Access – every 15 years
Continuous Evaluation (C/E): is a new program which eliminates the need for the above periodic reinvestigation. C/E means that all personnel are responsible for reporting to their Chain of Command any questionable or unfavorable information that is relevant to a security or clearance eligibility.