Our Vented Leash Plugs have been in surfboards and SUPs for since 2010 worldwide with no reports of degrading over time. We recently developed a new improved membrane we call "G-vent" to replace Goretex which is the standard venting material.
If you are concerned with longevity of the membrane then you can rinse with fresh water as the only thing that can do wrong with the membrane itself is getting clogged with salt particles from ocean water. But that is very unlikely since the microscopic membrane is smaller than water molecules.
You can be confident in the lifetime if our vented leash plugs.