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.