I have lived in every climate except artic. I fill the tank, the machine sits, I use the machine, I fill the tank, the machine sits, I use the machine. My gas tanks on everything is full everytime it sits. My generator (1964 4cyl army generator) sits years without starting, but the gas tank is topped off full. Never in 40 years have I ever had varnish or a carb problem due to fuel breaking down, Not lawn mowers, snow blowers, go-karts, boats ect. I wasted my money one time on Jello (sorry I meant Sta-Bil) for 3 machines. It turned into 3 projects. I won't put it in trash can out of fear i would have to clean it to make it hold trash again.