What is the inspection interval mandated by the FAA for the visual inspection of flight crew life vests?
ANSWER: The life vest manufacturer (not the FAA) specifies the life vest inspection and overhaul period. The FAA only mandates that the aircraft occupants have a life preserver available to them when operating over water.
An air carrier may have specific visual inspection requirements in their operations manual or maintenance program. For example, prior to each flight a visual inspection might be conducted to determine if any of the life vests are missing or the packaging has been tampered with. If they find this type of discrepancy, they would replace the life vest.