OK, let me throw my theory around about this topic for you folks to chew on, part of this is based on 20 years of working in dealerships on cars & part is derived from a discussion I had with one of the best computer Techs I ever met (he works underground in a mine setting up & maintaining a mirror backup system for one of the largest Hotel chains in the world). When I started using computers in 92, I fell into the theory they needed to be on 24-7 to keep them from surging themselves & cooling down etc...?? Anyway I probably read this stuff in Macworld cause that is all I read, He told me with much conviction, do not leave your computer on all the time, he asked me, do you leave your car run all the time? do you leave your furnace fan run all day? do you leave all the lights on in your house 24-7? Then why would you leave your computer on all he time, the processor, hard drive, the power supply, all are wear items, why are you making them work when you don't need them, he said it is good to restart your computer every day & even better to restart it a few times a day, you aren't afraid of surging it then are you? He said the guys that sell computers & parts sold those theories & a lot of people buy into them, I just stood there with my teeth in my mouth cause I didn't really have a reply, & after repairing things on Hondas, Porches, & Audis that were worn out for 20 years he kinda made sense, so now I don't leave them on all the time & if nothing else I am not getting hacked in the middle of the night & I am using less electric & I don't notice anything different, & the Mac starts itself up when I specify every morning so it is sitting there waiitng for me when I get there- whew, sorry for the long reply, I got my knee scoped this morning & I am bored- & remember I used the word theory a lot so don't flame me haha