Magi,
This subject has been discussed before and many users have a difference of opinion. You'll probably receive a number of different opinions here. I can only tell you what I do with our office computers, plus the suggestions I give to my few customers and what I do with my home computers. I've got a large number of machines that have lasted 5, 6, 7 years and more, so use your own judgement on this issue. Obviously, for most, the life of a computer can be longer than one wants to keep the computer, considering the major advancements that occur over the years.
Remember, if you're only talking about "power usage", then you will save power and money for that power by shutting it down frequently. There appears to be very little "extra" power used during the start up process.
But the main question here is how much "wear and tear" on the system occurs should it be turned on and off repeatedly throughout a day. How often should one turn off the computer in order to get maximum life from the PC?
First, I don't use "Power Management/Saving" options such as "Standby" because I've had problems waking up the computers afterward. I also don't use screen savers which hog resources. That's a personal choice that others may not agree with, but still, it's what I do. In regards to normal operations...In my opinion, I treat the PC monitor much like a television set. If I'm going to be leaving for less than 30-60 minutes, I leave it ON. If I'm going to be leaving for more than that, I turn the monitor OFF. If I'm going to be leaving for more than 3 hours or so, I turn OFF the computer tower/processing unit also.
Hope this helps.
Grif
That is the question! I would be grateful if anyone who knows about these things can settle an argument for me please: Is it better to leave my PC turned on because it consumes more power booting up than it does just sitting there doing nothing? Or, say, if I am going to be away from the PC for an hour, again does it consume more power turning it off then on back on again rather than sitting there doing nothing. In both cases, let's assume I'll have turned the monitor off.
Thanks in advance for any advice

Chowhound
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