Many questions tagged power are dealing with power-management. However, there are also many dealing with powering on/off the device, which would speak for keeping them separated. In this case, we should at least re-tag the relevant questions. Note that the excerpt of the power tag currently reads:
For questions about power-management, power on/off, and the like.
Just noticed, the power-management tag wiki excerpt reads:
All about how to get the most out of your device's ressources, especially managing power consumption
Which would be quite similar to battery-life (oops)...