I am not exaggerating when i say my PowerBook has only been turned off for at most a couple days, once or twice a year. Bottom line I bought it 2 years ago and the thing is still kicking fine no signs of degradation from such steady use. However it's a fact of life that the monitor will die sooner, unless you put it to sleep at night, its funny but i guess you could argue you wouldn't survive if you were left on or awake for 5 years straight.