I believe the biggest problem with any gasoline powered generator is letting them sit for a long time without running them. And not properly doing the storage procedure. Gasohol is a real killer for the carburetors. Oil changes are necessary to assure there is no oil contamination. Oil simply does not wear out it get contaminated from moisture, carbon, metal filings and etc. Since most generators do not have oil filters so it is necessary to change the oil more often. With metallurgy as good as it is today, metal filings from wear is not that bad. Carbon, crud and moisture are a bigger problem. Also, generators that require armature brushes should be avoided..