Which of the following is a critical maintenance task for smoke detectors?

Replacing batteries periodically is a critical maintenance task for smoke detectors because it ensures that the devices are always in working order and can effectively detect smoke and alert occupants in the event of a fire. Smoke detectors often rely on batteries to function, and without a steady power source, their ability to operate can be compromised. Regularly checking and replacing the batteries according to the manufacturer’s recommendations helps prevent false alarms or, more importantly, the failure of the detector to activate when needed.

Other tasks like cleaning the housing, while beneficial for maintenance, do not address the core function of the smoke detector as directly as battery replacement. Installing new units every month is also excessive and not practical for maintaining operational smoke detectors. Painting over detectors can actually hinder their functionality, as it might block or obscure the sensor, thereby preventing accurate detection of smoke.