We do not know what you mean by "PFD", please do not use abbreviations. But the answer would be when the instructions for the "PFD" say it needs to be replaced.
According to the manufacturers instructions.
You should replace the CO2 cylinder on your inflatable PFD (personal flotation device) after each use, especially if it has been activated. Additionally, regularly inspect the cylinder for signs of corrosion, damage, or a low pressure indicator, and replace it if any issues are found. It's also advisable to replace the cylinder according to the manufacturer’s guidelines, typically every 2-3 years, even if it hasn't been used. Always ensure you have a fully charged and functional CO2 cylinder before using the PFD.
For the newer Inflatable PFDs, most manufactures will tell you when you should replace your cylinder, and most have an easily viewable inflator status. For instance - The Mustang Deluxe Automatic Inflatable PFD: Universal fit states: No inflator maintenance is require for 5 years unless the PFD has been inflated. You can easily view the inflator status and replacement date through the safety inspection window. Green indicates ready for use. However, each manufacturer can have different specification, so it's best to check with your manufacturer and for your specific vest type. For more information regarding the Inflatables, visit: The link below
For the newer Inflatable PFDs, most manufactures will tell you when you should replace your cylinder, and most have an easily viewable inflator status. For instance - The Mustang Deluxe Automatic Inflatable PFD: Universal fit states: No inflator maintenance is require for 5 years unless the PFD has been inflated. You can easily view the inflator status and replacement date through the safety inspection window. Green indicates ready for use. However, each manufacturer can have different specification, so it's best to check with your manufacturer and for your specific vest type. For more information regarding the Inflatables, visit: The link below
Inflatable PFD
Every time it is worn!
A PFD for everyone aboard
a pfd for everyone aboard
a pfd for everyone aboard
a PFD for everyone aboard
Wearing an inflatable PFD while on a personal watercraft.
In Iowa, inflatable personal flotation devices (PFDs) can be legally used for boating activities, but they must be worn at all times by individuals in certain situations. Specifically, inflatable PFDs are permitted for use by adults in boats over 16 feet in length, as long as they are approved by the U.S. Coast Guard. However, children under 13 years old must wear a traditional, non-inflatable PFD. It's essential to ensure that the inflatable PFD is properly maintained and has been fully inflated before use.