Hi
Battery life varies depending on use and other factors. Examples are detailed here:
http://www.apple.com/watch/battery.html
Apple's tips for maximising battery life on Apple Watch are detailed here:
http://www.apple.com/batteries/maximizing-performance/#watchtips
If your Apple Watch is experiencing significantly shorter battery life than Apple's examples suggest that you should expect and/or than you were experiencing before, then your Apple Watch may require battery service.
Before contacting Apple, it may help to follow these steps, which have previously resolved battery life issues for other users, including those experienced after installing software updates, when their usage has not changed:
Restart both your iPhone and your Apple Watch, turning both off together and then restarting your iPhone first:
If you have ever (not necessarily recently) previously used the Workout app and/or any third-party fitness or sleep tracking apps to record workouts on your watch, check on your watch to see whether there is a paused activity within any of them. If there is, end that activity from within the app on your watch (not your iPhone).
- If in doubt, remove any such third-party apps from your Apple Watch.
Unpair and re-pair your Apple Watch:
- The Watch app on your iPhone takes a backup of your watch automatically when unpairing via the app.
- When setting it up again, initially choose to Restore from Backup. Most data and settings will be restored, with some exceptions (eg Apple Pay cards, passcode).
- If the issue persists, consider instead unpairing and setting it up as a new watch.
- Unpair your Apple Watch and iPhone - Apple Support
- Set up your Apple Watch - Apple Support
Some users have previously experienced battery life issues in connection with using corporate profiles and/or Exchange Calendars. If you are using an Exchange Calendar, one or more of these steps may help:
- Archive your Exchange Calendar for all items before today.
- Remove / delete all old inbox messages relating to calendar invites (accept and decline notifications).
- Create a rule in your Outlook Mail account that moves all future accept and decline replies, immediately upon receipt, into a separate mail folder that does not sync with your iPhone and Apple Watch.
- Check your Exchange Calendar for errors.
Finally, it may help to:
- Remove third-party apps from the Dock and/or from your watch and then monitor battery performance after adding them back, one at a time.
- Remove watch face complications and monitor battery performance as you add them back:
Having tried the previous steps, if the issue persists, I suggest contacting Apple Support (remote diagnostics and/or mail-in service may be available, if required), making a Genius Bar reservation or visiting an Apple Authorised Service Provider for assistance, including - if recommended - to have your watch inspected and serviced: