 You don't recharge your refrigerator in your house. You service it when it breaks. And that's how the new air conditioners are. That's how you need to think of it. They do not really need much other than cleaning the condenser, checking the belt, making sure the cabin air filter is clean, the evaporator is clean, the air intake at the base of the windshield is clean to get the air in there. That's really the only maintenance you need to do.