Personally I feel that we’ve gone past the days to have to worry about CPU cycle and power usage. The OS is smart enough to handle all that better than a human intervention. At least in my usage it works absolutely fine without issue and also helps me not to worry about things like that.I keep it turned off. If I'm missing out on anything I'm not aware. I don't see why I need to have apps using power and cpu resources refreshing in the background when not in use. It's not like it takes them long to start up or retrieve data when I'm ready to use them.