Some of those need power thuugh. We have a TV that we don't have a cable box connected to and just let it tune the basic cable channles that it can without a cable box. Unplugging it you have to let it rescan for channels again. Cable boxes, satalite recivers, DVR's all need to be powered on to be able to get updates and such. Most people have their computers do virus scans, backups, etc at night.
Last job I worked I wore the desktop support hat. One user kept complaining about her computer being really slow and I never found anything wrong so I checked in the morning when she first came in, she was turning it off at night so the AV scan was running first thing in the morning and was taking hours since she was trying to work while it was running. We had to run Av scan every night when I first came in there because the desktops were in bad shape, users had admin rights, using internet explorer instead of a safe browser, etc so there were virus'es all over.


Somehting I've done with my home is go to the power companies web site and download my usage history (they keep three years) so as I make a change I can see if it made any effect. Plot it on a spreadsheet graph and see if the mean goes up or down over time.