Leaving it on, not asleep, not allowing the hard drive or monitor to power down, will certainly reduce its life, because the screen and hard drive both have finite lifetimes. This is true of every computer. If you let the display and hard drive power down, the negative impact will be a lot less, but over time, yes, it will still have a negative impact on the computer. Look at servers -- they break, eventually. And parts need to be replaced. That's pretty much how it is with any computer hardware that runs 24/7, and notebooks are not really meant to be running 24/7/365.DRL453 said:i will be a new mac user when my new powerbook arrives but i was just wondering if i can leave the computer on constantly while plugged in. will this do any damage in the long run?