When should a fire extinguisher be removed from service?

A fire extinguisher should be removed from service whenever it has been used. This is because even if it appears to be fully recharged and operational after use, there might be internal damage or a decrease in pressure that could impair its effectiveness in a future emergency. Once an extinguisher has discharged, it is essential to have it inspected, serviced, and refilled by a qualified professional to ensure its reliability and readiness for any fire incidents that may occur in the future.

The other options do not align with standards for fire safety equipment. Aesthetic issues do not affect the functionality of an extinguisher; thus, it should not be removed from service solely for that reason. Not following a maintenance schedule indicates a potential concern about the extinguisher's condition but does not automatically necessitate removal. Lastly, while leaking is certainly a valid reason to take an extinguisher out of service, it is just one specific instance when an extinguisher should be removed, whereas usage is a broader and more definitive reason.