Is it true for desktops that they shouldn't be powered on and off constantly?

I don’t buy that argument.

Although it’s true that turning things on and off constantly isn’t good for their overall longevity, it’s important to realize that they’re machines. The more you use a machine, the faster it will wear out.

Not to mention the unnecessary use of energy. When I started turning my desktop off overnight my electric bill went down $20 per month.

Makes no sense to me either. PCs last longer if they’re allowed to cool down completely and that doesn’t happen if they’re left permanently switched on.

They have this stupid rule at work about leaving PCs switched on permanently, and then they wonder why they all keep going faulty.

Not really. The components that would benefit from powering down undergo the same thermal stresses when put to sleep as they do from being turned off entirely. For instance, the CPU draws a considerable amount of power (~100 Watts, though highly variable depending on the CPU and how much load it’s under) and video cards draw even more. And that power draw generates heat, which causes metal to expand.

The argument against powering down completely is that it will keep those components warm and thus prevent them from contracting; it’s the cycle of repeated expansion and contraction that eventually causes metal fatigue which causes failure. However, going from drawing 250–600W to drawing less than 20W doesn’t do that; the power draw isn’t enough to keep stuff hot, so it cools and contracts the same way it would if shut down completely.

@downtide Actually, leaving them on all the time is better if the things are kept well-ventilated and clean. However, many computers have sub-par cooling, are placed with inadequate ventilation, and/or are allowed to collect dust and lint that clogs the heatsinks. Once any (or all) of those happen, cooling degrades, temperatures rise, and components fail. I know people who leave their PCs on 24/7 for a couple of years at a time without issue.
In other words, it’s not the leaving them on that hurts, but that it is done wrong.

@FutureMemory Are you sure your electric bill went down that much because you turned off your computer each night?? That’s quite a bit .. computers just don’t use that much electricity. My husband is an engineer for our power company and he thinks maybe something else changed on your bill (rates) and was included in that decrease.

@JustPlainBarb Hmmm well, my desktop set up is really ghetto meaning when I have it on there’s multiple house fans blowing on it (with the side panel of the CPU removed) at all times. A lot of electricity is being pumped into that room when I have the computer on. I may have also been leaving multiple lights on in the room.

@FutureMemory Thanks for the clarification. :)

It depends his argument. You can wear out the electrical parts over time, by turning them on and off frequently. I honestly doubt that once or so a day would really do it though, unless you’re looking at a sample time of like 5–10 years.

In that sense it makes more sense to leave it in sleep, but that can actually cause your computer to run slower over time, necessitating a restart to get it back to regular/full speed.

It used to make a lot bigger difference for reliability to leave your electronics on all the time. The solder joints and other connections would crack and separate and become unreliable when power/heat cycled a lot.

Materials technology and connection technology has advanced to the point it doesn’t matter much these days. And as @jerv points out you’re more likely to suffer from heat-related problems if you leave the machine on non-stop than anything else.

I’ve always left my computers on/sleep. My last desktop lasted 8+years without ever powering down.

Also, don’t know what OS you are running, but macs run daily/weekly/monthly unix maintainance scripts in the night and if your computer is off those don’t run.

LOL… computers are pretty hearty guys, and the ‘on or off’ issue really only boils down to two things: Your power consumption / conservation habits or needs, and care and upkeep of your machine. If you want to save power, turn it off. If not, leave it on but set the power configurations for when it’s not in use (to sleep / hibernate). Other than that, if you take good care of your machine, make sure the CPU, etc gets the proper cooling, ventilation and the guts get dusted now and then, you’re fine either way.

And remember, computers rarely die of old age from turning them off and on too much, or not turning them off often enough. (Unless you constantly flip back and forth multiple times every single day). Most computers die from other causes, faulty power supplies, bad capacitors, fried CPUs, bad motherboards, broken fans, dropped or knocked over, animal attacks, spilled energy drinks, etc etc.

And after all, just consider servers…... Hey Fluther sysadmins, when was the last time you turned off your web servers? LOL

As far as I can determine, leaving on my pc for a month costs me about $5.00. Switching in on and off twice a day, would wear out the switches much faster. And, I am sure the switches cost more than $5.00 each.

Based on these figures, I am leaving my pc on all the time.

So what I gather from this whole shebang is: Turning it on and off frequently can be detrimental. Turning it on/off once a day can save electricity.

@whitecarnations Personally, that is how I do it. Whenever I put the thing to sleep, the cats usually find a way to wake it (and/or me) up in the middle of the night. With multiple cooling fans and some bright LEDs inside, the thing is too loud and bright to leave on. Therefore, full shutdown every night.