You might not think of ceilings as needing maintenance-but indeed, they do need occasional attention. First, they need to be kept clean and, in particular, free of cobwebs, which can trap dust and grease particles. You should also watch for any sign of sags, cracks, or water stains. Finally, examine lights, fans, and hooks or hangers. They should hang securely from the ceiling, and there should be no cracks expanding around them.