I leave mine in standby, or off between listening. I listen pretty much daily and have not noticed any increase in my bill.
BAT REX power consumption
I'm considering moving to a BAT REX, but have some concerns regarding the power consumption. The specs indicate 470 watts total between the power supply and main chassis. Even the 52SE puts out 250 watts. I don't think I've seen any preamp putting out more than 100 watts, with most consuming considerably less. Is this something, outside of increasing one's electric bills, to be concerned about?