I run mine at least once a month and often a bit more. I use the AC for load in warmer weather and an 1500 W electric heater to load it in cooler weather. You need to run it until the crankcase temperature stabilizes to drive out condensation, and the exhaust system dries out. I run it at least a half hour, sometimes more in cooler weather. Good time to vacuum and do other tasks requiring 120 volts.