John, I have an 03 Monterey and the only time I use it is when I am not connected to shore power and want to make a pot of coffee or watch the tv. The thing you must remember is to put the refrigerator on gas when on the inverter or it will take the batterys down more rapidly. Some people turn it on with shore power connected and it goes into standby mode. If shore power fails it comes online keeping things running. I prefer to leave it off and then there is no doubt which source of power is active. Just another tip, keep the battery water serviced as you are probably connected to shore power most of the time. I spend the winter in Florida and have to add approximately 100 cc of distilled water to each cell every 2 months. Hope this clears the air for you.
George