I had the same experience. I even gave my series 1 to my mom after I upgraded this year. It lasted me a long time, but I wanna swim with my watch, dammit. That being said my friend had the series 6 and said the battery life degraded massively after a year.
Same. I’m using a 7 now - my wife is still on my 0 - and I’ve no issues with the battery on the 7; I still get 1.25-1.5 days for a charge.
I think if you run the battery down to zero, every day, like on an iPhone or an EV, it’s going to degrade the batteries. I’m still using an iPhone 11, and getting again over a days use on charge. I don’t know if everyone can say that, but I’ve been really careful with never going under 20% for the battery before charging. That’s kind of how we just do lithium ion these days.
Like I said to the other fella, I got up to the series 7 before my wife took it and carried on. I bought an EV about three years ago, and for the two years before that, I read everything I could about lithium ion batteries, so I’m really cautious and careful with my tools. I know who a lot of people don’t want to think about that, but hey… It’s your money.