>I've spent 29 years in the semiconductor industry and >have qualified many product after various "stress" >tests. > >No-one has ever suggested a "turn-on, turn-off" test >:-) > >We do however perform accelerated life tests at above >normal Voltages and temperatures. I have to tell you >that semiconductors DO wear out with continuous usage. > <snip> Thank you, John <all>...for an interesting & informative thread. I'm going to begin shutting down when I'm through for the day, and sleeping when I'm inactive. I used to do this ALL the time, then for whatever reason, I stopped doing it about a year ago. Thanks for the reminder to protect my mac AND conserve energy. jonny ///