Interesting after conflicting Apple phone tech support, I visited Apple store genius bar to see about feasibility of getting watch 7 battery service. He said they won't do it until diagnostics show it needs replacement. I asked if similar to I believe phone, if the battery life drops below 80 percent, will battery health check then say it needs servicing. He stated not necessarily, he has seen some battery watch health check in the low 70s percent and still state to be ok. He said, usually diagnostics won't fail until a sharp sudden drop, rather then a gradual, steady decline. Another conflicting statement when I asked if series 10 had still had blood oxygen sensor that could possibly be enabled if lawsuit settled, he said not, it's not even present on the watch. I thought non-USA series 10 watches still had the feature?