Just finished testing my old AirPods (21 months old) against a new pair I got for Christmas. It's a little hard to get exact numbers, but I paired the old case with one new and one old earpiece and watched the old one deplete much faster than the new one. I would have to charge the old earpiece a time or two to keep it from dying while the new one had plenty of juice left. I then swapped earpieces and cases and repeated...The 21 month old earpieces have from 1/3 to 1/2 the capacity of the new ones. Seems like one earpiece was slightly better than the other, but I'm comparing new vs old so that difference may be in the new pair rather than the old pair. The old case has about 75% capacity left. I'm actually keeping the new earpieces with the old case and figure I can get about 4 charges out of the case before it's completely dead. My wife can have the old earpieces with the new case. LOL! I doubt she'll notice and she doesn't use them like I do. I will say that the old pair were still very functional. They would deplete pretty quickly on a phone call but they charge up to 100% much quicker than the new ones (less capacity...same charge rate, I assume). I never had any issues making calls or listening to music with the old ones; just had to charge them when they dinged at me. On the other side of the argument that's horrific battery degradation in the earpieces for less than 2 years! My guess is that the earpieces stay fully charged 90+% of the time, which can be hard on batteries.
