Your AC refrigerant isn't consumed like gas. If it's low, you have a leak. Stop topping it off and fix the leak instead. Yearly low refrigerant means something is broken, not that your system needs maintenance.
Chapters
Refrigerant isn't like gas in your car, okay? It doesn't get used up. If it's low, you have a leak and no, you just don't add a little bit every year, it needs to be topped off. I need a couple pounds of refrigerant. No, you don't. What are you talking about? Stop thinking that way. If you're low refrigerant, you have a leak. And no, every year is not normal. It's like having a hole in your gas tank. You don't just keep putting more gas in. No, you fix the leak. That is the more economical and fixed versus doing what we call a band aid repair, which is ignore the leak, keep adding refrigerant, keep adding gas, and we might get through another summer.