Hi Guy,
You don't need to power down anything!
For talking sake, say you're using Volumio and playing a particular track. Simply stop the track, by clicking on the stop button, close down volumio (and by that I simply mean closing the opened tab on your desktop, not actually shutting down anything in the operating system), switch off your laptop, or whatever other device you're using (and if you want your hi-fi system), and go to bed.
In the morning, switch your laptop and hi-fi system back on, and continue where you left off. No need to power down anything relating to the RPi.
Leave it ALL on, ALWAYS. Simples!
My RPi, associated linear PSU, and NAS box (containing all my music files) remain powered up 24/7.
Marco.