I won't repeat any of the sage advice above except to say that I'd agree with leaving the SS on and turning power tubes on and off if you aren't using them for longer periods.
As a note of further info, should you be curious or want to try to convince the wife or S.O. that it's not too expensive - there are simple devices available to directly measure power consumption when plugged into a wall outlet. I've been using one to monitor a few of our appliances to figure out why our electric bill is rather high. The one I purchased is a
"Kill-a-Watt" which costs about $35 online. Once plugged in you plug in the appliance you wish to monitor. The timer starts running as soon as a device is plugged in. Over whatever period of time you leave it plugged in it will measure the amount of electicity in Kwh (killowatt hours) that the specific device has used, and over what period of time it consumed that amount of power. You can then translate that into usage per/day/month/year/etc. and put a dollars and cents amount to the use based upon your local rates. I tested my home rig, consisting of a 100wpc SS amp (class AB/A), A DAC, and a transport. In my case I tested over a 24 hour period with typical use, and all components on 24/7. The results? With our rather expensive urban summer rate averaging around .07 cents/Kwh the entire rig costs about 13 cents/day to leave on. In contrast our fridge costs about .18 cents per day to run 24/7. YMMV widely regarding your rig depending upon just what you are running. Class A gear is going to cost significantly more to leave on. I don't think transports and DACs cost more than a few pennies a day. So if you are concerned or just curious, for $35 or less you can find out. I even came across a DIY version of an electrical consumption meter online, but lost track of the URL.
Marco