There is no right or wrong answer to this one -- even the so-called "pros" don't agree. Do what you feel comfortable with and makes sense in your life and where you live. Electric use of pcs these days is minimal; and pcs tend to run cool for the most part. Your furnace, air conditioner, refrigerator and the like remain operation 24/7 and they seem no the worse for it. On the other hand, if a pc isn't going to be used for hours, it probably doesn't make sense to keep it running either. And if you live in an area where thunder and lightning is a concern, I wouldn't leave it running during those times. In most instances, you will choose to replace a pc long before it wears out anyway. It is a fun question to discuss -- and some get highly emotional on it -- but there is no real right or wrong answer except for what seems to make sense in your world. What I wouldn't do is continually turn a pc on or off -- and this is conventional advice for most electrical run things such as tvs, lights and radios. My relationship with God begins with trust. It also continues in trust. Pastor Mark Cummmins, First Baptist church of Ocala, sermon, 09/14/08 http://wm.thegospel.com/ocala/080914_drcummins.wmv