Cleaning the lint trap before each load will prevent a fire hazard, save energy and make your clothes dry faster. To avoid wasting energy and over-drying clothes, use the automatic dry cycle. Once a year or so, use a dry paint brush to clean lint from the corners and cracks in the interior of the dryer and around the door. If you often wash athletic shoes and similar items, check to see if the manufacturer of your dryer sells a rack accessory that mounts to the back of the dryer. It will help such items dry quicker and more quietly.
If you have a traditional sheet-metal dryer exhaust vent, you should clean it about every five years. Disconnect the pipe at both ends and use a broom handle to push a rag through the pipe to remove the accumulated lint. If screws were used to hold the pipes together, replace them with foil tape. The screws catch lint flowing through the duct and can cause clogging. If you have the very thin, cheap plastic dryer exhaust tubes, they may be flammable and should be replaced.