I know of many forum users that leave their B2's in standby. I tend to switch mine off because it is connected (electrically) to my old amplifier which does need to be powered off when not in use.
Of course also remember , if you have set you B2 in NAS mode, you would want to keep the NAS on your LAN 24/7 for other devices to access.
The Raspberry Pi computer, round which Brennans are now built is very robust, consumes very little power and is quite happy being left on permanently.
The only thing you need to do is set the front screen to go dark after a short period of inactivity. See the maintenance menu form the front panel display - "Screensaver -Screensaver settings for when B2 is in standby mode - 0 = screensaver off, 1-15 = display brightness - 1 = dim, 15 = bright, 16 = display off."
Fred