I've got an Apple Watch Series 9 that I've been using for a year now. For the last couple of months the battery's been draining really fast - I'll charge it to 100% in the morning and by evening it's down to 15-20%. It used to easily last until the second day. What could this be - is the battery wearing out or some kind of software glitch?
I had a similar situation - my watch was working fine, then suddenly started draining really fast, especially if I turned on Always-On Display or got a lot of notifications! Usually a full restart of the watch helps (turning it off and back on), and you should also check in settings whether there are any apps eating up the battery - sometimes an update can start misbehaving.
If a restart doesn't fix it, it's probably battery wear showing up, especially if you've been using it actively for a year. Over a year or so the battery can degrade by 20-30%, which is totally normal! You can reach out to Apple - they'll check the battery health and offer a replacement if needed.
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