While BCDs don't have an explicit service life, the modern BCD bladder and fittings should last at least 10 to 15 years, and with proper storage we've seen plenty of them last significantly longer. As they age, the plasticizers in the materials begin to deteriorate, causing seals or vinyl welds to fail and molded fittings to become brittle resulting in leaks. The two factors that have the most effect on accelerated aging is exposure to sunlight (UV) and especially storage near electrical or combustion devices (Ozone.) Usage in swimming pools will also accelerate aging due to effects of pool chemicals (Chlorine and Bromine.) In our experience, once the BCD begins to exhibit any problem due to aging, a simple repair is ultimately not cost effective because further problems in other components are sure to follow along shortly. Statistics from DAN suggest that a failure of buoyancy control can be one of the most life threatening types of dive accidents. Once your BCD begins to exhibit issues due to aging, it's probably time to consider replacing your entire BCD rather than making a repair.