When should you replace the co2 cartridge in a pfd?

You should replace the CO2 cartridge in a personal flotation device (PFD) after every use if it has been activated. Additionally, it's important to inspect the cartridge regularly for signs of corrosion, damage, or if the indicator shows that it's been used. If the cartridge is approaching its expiration date or if you are unsure of its condition, it’s best to replace it to ensure the PFD functions properly in an emergency. Always follow the manufacturer's guidelines for maintenance and replacement.