I recently noticed the case for my Air Pods Pro Lightning is quickly losing a charge. So I pulled the pods out about 4-5 days ago, left the case alone. It was almost dead today. Model number is A2698 and firmware version is 8B39. They aren't my primary. They were introduced in 2022 so that's probably when I bought them. As I'm typing this I'm thinking four years, yeah, I guess it's time for the battery to die. Never experienced this though. And they are just a backup pair.