Final answer:
Portable fire extinguishers should be inspected at least once a month for any visible signs of damage or corrosion. An annual maintenance check should be conducted by a certified professional to ensure their proper functioning.
Step-by-step explanation:
Portable fire extinguishers should be regularly inspected and maintained to ensure their proper functioning and readiness in case of a fire emergency. According to the National Fire Protection Association (NFPA), fire extinguishers should be inspected at least once a month to check for any visible signs of damage or corrosion and to ensure that they are in their designated locations. In addition to the monthly visual inspection, a more thorough annual maintenance check should be conducted by a certified professional or a fire protection service company. During this annual inspection, the fire extinguishers are inspected internally and externally, and any necessary repairs or recharging are performed to ensure that they are in proper working order.