Ceiling fans make noise for a variety of reasons, including loose fasteners, a buildup of dirt and dust, and worn-out parts. In most cases, a noisy ceiling fan is an easy repair. If you’re handy, you can tighten screws, apply lubricant, and give the fan a thorough cleaning to see if it fixes the problem.
You maintain ceiling fans by cleaning them. They have sealed bearings so they don't usually need any type of lubrication. You'll want to dust the blades regularly, using a vacuum cleaner to get into inaccessible areas. You may want to remove the light cover and clean it out and any exposed areas for dust. You may need to use a wet cleaning solution of some kind, particularly on fans near kitchen areas, where grease buildup mixes with dust to create grime that can destroy your fan.
Numerous things can cause a ceiling fan to stop working, including the components wearing out through constant use. Other issues include the following:
Wires loosening over time due to fan movement or faulty wiring
Grime and dirt buildup that eventually work their way into the moving parts of the fan
Electronic components failing over time from constant use
Physical impacts with household items