Changing the oil involves changing the engine oil and replacing the oil filter and sump plug washer.
This depends on the vehicle manufacturer and your driving habits (how far you travel each year, whether you frequently stop and start, etc.). However, it is generally recommended to perform an oil change every year, or every 7,000 to 10,000 miles.
The oil is made up of chain molecules that position themselves between moving metal parts. These molecules prevent the metal parts from coming into direct contact, thereby reducing friction and wear. When the engine is running, the molecules gradually wear down and disintegrate, eventually reaching a point where they are no longer providing lubrication. Changing the oil regularly therefore helps you avoid expensive repairs.
This article was written with assistance from the Bosch Car Services network of garages.