Apple states that the Series 9 (and older) and the Watch SE models are both good for 18 hours of battery life. It also states the Apple Watch Ultra 2 (and Ultra) has 36 hours of battery life.
The Apple Watch SE (starting at $249 ... and significantly more battery life. However, it lacks some niceties of the Series 8 (starting at $399), such as an always-on display and sensors for ...
Apple's default answer is Low Power Mode, but a mistake you might be making is waiting until your iPhone prompts you to turn it on. The longer Low Power Mode is on, the more batte ...