The soffit on a house is the underside of the eaves. It extends from the side of the house to the edge of the eaves. It's typically an overhang around the frame of the house. The fascia is made from wood or sheet metal, and runs horizontally under the edge of the roof.
Both are exposed, and are therefore susceptible to damage from the elements.
Mould and mildew can also build up on aluminum or vinyl soffits, so it's important to clean them regularly with soap or bleach (but not too much, as it can change the colour of the soffits) and a brush. Never use a power washer to clean your soffits, as that much pressure can push the water into your attic.
The biggest danger to your soffits and fascia are wayward baseballs, basketballs and footballs. When struck, the soffits and fascias can bend, and can bend into the attic. Sometimes, they can just be pulled back into position, but if they keep bending, they will need to be properly repaired. Removing these pieces can be tricky without damaging the other panels, so it's often best to leave the repairs to the experts.
Fyfe's Roofing offers soffit and fascia repair services. In the event that the piece cannot be repaired, they can replace it.
Soffits and fascias that are made of wood are very susceptible to water damage, which can be caused by faulty flashing, ice dams, damaged shingles or gutters. These parts can begin to rot and will need to be replaced. Replacing the wood soffits and fascias with metal ones is advisable, as obviously metal is more durable and will not rot.