Remove the cover, vacuum dust, wipe blades with soapy water, and clear exterior vent flaps.

Signs include excessive noise, weak airflow, visible mold/moisture buildup, or the fan not turning on. If it’s over 10 years old or inefficient at removing humidity, consider replacing it.

Yes, if the electrical box is rated for ceiling fans (marked "fan-rated"). If not, replace it with a reinforced metal box.