Movement oil collects dust and other contaminants from the air. These contaminants can be abrasive and the oil can harden. For this reason, it is necessary to have the movement cleaned and oiled. The frequency of cleaning and oiling depends upon several factors, some of which include the humidity and temperature controls and cleanliness of the environment. Based on these factors, oiling should be performed every 2 to 5 years and thorough cleaning every 5 to 10 years.