Over a week with a Series 2 42mm (which has a >30% larger battery v. Series 0!), I have consistently finished each day at 25-40% battery left. I wonder whether a dimmed screen "always on" feature will be added to the existing hardware with (or before) Watch OS4/Series 3. For those who think the hardware needs to become more efficient, how much more efficient? Why is this feature so common with AndroidWear devices? Appreciate any comments/thoughts!