Should I Charge My Apple Watch Every Day. As others have said dont worry about it. Another thing is that.

Considering just how intensive the use for an Apple Watch is you will probably need to charge the watch every other day anyway and the night seems to be the best time to do it since you do not need the watch to record anything unless you want to keep track of your sleep patterns. Sure you are right. Charging will stop automatically when the battery is fully charged and start again if and when required due to ongoing battery usage.
Apple advises that you can charge Apple Watch whenever you want.
And now we have our first real details of how long it will last. And a 100 full charge takes 25 hours. Charge your Apple lithium-ion battery whenever you want. As others have said dont worry about it.

