Just started paying attention to our sub recently: it had started to drop out, only working intermittently. Then seemed to pack it in completely. Theoretically it can be plugged in and switched on constantly, and will only use significant power when it's active. In practice I found whenever I put my hand on the back plate, it was VERY warm. I don't have a kill-o-watt or similar to see what's actually being consumed, but I've read that anything that feels warm is consuming power, and the sub was pretty toasty, even at idle. Long story short, with it's near non-preformance of late, it's getting dropped off for repair right now, hopefully the repair is less than cost of replacement. One thing I started doing, just in the last week, was to plug the sub into a switched outlet on the back of the amp. The outlet's rated for 100 watts, and the sub stated requirement is 70 watts. So I think I'm ok. What this does is shut the sub off whenever the amp's not on. Hopefully save some juice.