Approximately 80% In my rough estimation. It’s fine for a workout which is my threshold for usability, but has begun to suffer on long flights. I use these while working out 3 to 5 times per week and on trips.

This seems generally in line with lithium ion batteries in smart phones.

It’s kind of hard to tell with my 2 year old Pro 2s. I treat mine like dog shit. They’re in use constantly for 8 hours of remote meetings, and I leave them in for podcasts at night. I throw them in the case at lunch and during dinner, but it’s not because I’m getting a battery warning. It’s because I’m stepping away from the desk. All in all, I hit these things pretty hard.

My guess is that they’re probably down to 4+ hours of audio and 3+ hours of call time after 2 years. Long enough that I’m likely going to take a break, and put them in the case before I hear a battery warning.

That said, my old non-pro Gen 1 AirPods were really starting to struggle after 2 years. After 2 years I needed to swap between right and left buds to get through an hour call. They made it about 45min with the mic on, and those didn’t have ANC and head tracking.