For those of us that have generators for standby use at our homes, we need to drag them out every thirty days or so and run them, preferably under load.

I shoot for 30 days, probably make 60 and run my generator with an electric heater hooked up.

This is really the only way you know its going to work when you need it.

Data centers will typically run their generators without load once a week and under load once a month.