All eletrical gear, audio or otherwise, was designed to be used, ie: ON. All specifications are produced using samples that have been on for many hours in the lab, connected as they are to be used in the "real world". I have been at this for over 30 years, and have always left everything I own on all the time, and I have never had a problem. The only thing that could possibly happen is that there could be a "brown out" (ie: voltage drops below the norm momentarily), a spike (voltage increases above the norm momentarily) or it shuts down altogether. You will know from experience if you have lived in a particular place for a long time how reliable the electrical service is. The electrical utility which provides you with your "volts" also has over and under voltage limiters in place for this reason. They are not interested in frying Mrs. Jones as she irons her clothes, or blowing up every pizza oven in town just before the big game, the resulting lawsuits would be staggering, For really sensitive appliances like computers, you can buy surge suppresors (questionable) or UPC units (better bet). Most of the products I have seen over the years produced to deal with this "problem" over the years don't work, and most of the rheteric I have heard and read was designed just to scare you. Leave your gear on, you will be fine.
Leaving Amps on
I am wondering, in the case of which is best for the speaker, is it best to leave the amps on all the time, or shut them off between use. I know that turning them on and off causes heat expansion in voice coils leading to stretching; The main reason that pro audio setups that are permanent stay powered up all the time. But, is it really best? Can I also cause long term damage to the speaker by leaving it powered up with no signal being sent? I just recently read an article that said too much continuous power can burn the parts in the coil. Can anyone help? Thanks in Advanced! Sam