There are some things to consider. Where is it stored ? is it potable, where does it live ? outside, inside , enclosed , etc.. Is it in a humid wet climate or dry dusty climate. Many factors come into play for proper maintenance . Just because you run it doesn't mean the gasoline will get better. Gas will go sour after 3 months according to gasoline manufacturers. Depends if you use alcohol based fuels or non alcohol based fuels.Gasoline is the biggest culprit. Best answer is to follow manufacturer recommendations but no matter what always run fresh fuel. I drain my fuel tank if prolonged storage and run a detergent through before shutting it down.