Usually at the beginning of the heating season, and again at the beginning of the cooling season. More often if needed. The frequency is also dependent on the individual house, such as a house with pets versus no pets etc.
Called oil canning it is often related to airflow. Too much air will cause the ducts to swell like a balloon and the metal pops or creaks. Modern furnaces move lots of air and need to have correctly sized duct work and need the furnace properly set up when installed.