Is It Safe To Leave A Computer On All The Time?

Posted February 13, 2009 7:00 am by with 27 comments

Periodically I am asked whether it’s “safe” to leave a computer on all the time. The answer is yes if it’s a desktop (meaning not a laptop).

Chances are if you’ve been using computers long enough you’ve encountered at least one instance where some type of hardware failure occurred right as you turned on the box – and I’m betting it had something to do with a part that continually rotates when active.

Continually rotating parts in a computer are fans and hard drives (on the inside), and the most “grunt” needed is when they spin up from an absolute stop. When spinning they don’t have to work as hard.

To note: A DVD drive does not continually rotate. This is because when not using it, it doesn’t spin at all whatsoever even when the box is on.

Concerning hard drives:

It’s a good bet if you’ve ever seen a hard drive failure, it probably happened from a “cold” start, then the infamous “disk not found” message appeared.

Concerning fans:

Fans accumulate dust whether you want them to or not. This adds weight to the fan blades and can also dry out the bearing(s). If the fans stay spinning they will continue to do so almost indefinitely. However if they’re old and clogged up with dirt (including the dirt you can’t see or clean out), one day they simply won’t spin up from a cold start at all.

Starting up a hard drive from an absolute stop requires the most effort from it just to get it spinning – and this follows suit with coolant fans.

I sincerely do subscribe to the theory that having the computer on all the time is safe and does make it last longer.

In the way I have my personal desktop box set up, I specifically set the hard drives to never “sleep” because it’s essentially the same as starting a drive cold.

I want to note this is my personal opinion on whether leaving a computer box on all the time is safe or not. Based on my personal experience, anything the moves in a computer is better off if you keep it moving and helps to prevent premature failure.

27 responses to Is It Safe To Leave A Computer On All The Time?

  1. Steve Stone February 13th, 2009 at 10:03 am

    I’m going to show my age. Back in the dark ages I ran a landline BBS, networked ala Fidonet. The machine was a 486 with qty 2. fast SCSI 2 hard drives. It ran 24×7 for years. Every couple of months I would power down the system for maintenance.
    When powering things back up the bearings in those SCSI drives would scream for 30 minutes until the temps stabilized. I once had a less than 10gb Maxtor drive that went up in flames during a power on. The controller chip on the bottom of the drive lost all its smoke. It did not like to be power cycled. Fan and drive bearings were my biggest problems. I once built an inexpensive tower for my wife based on a $30 case/power supply combo. The power supply smoked during a power on sequence. It was good news for me, gave me an excuse to put a decent supply in that machine that did not throw RFI across all the ham radio bands. So I agree with you Rich. I also had a couple of HV circuits smoke in CRT displays. We don’t have to worry about that today.

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  2. Bonita S February 13th, 2009 at 8:52 pm

    From this, should I infer that it is NOT safe to leave a laptop on all the time? I bought one about a month ago and do leave it on almost all the time for same reasons I used to leave desktop on – it’s instantly available and usable. I get up in the morning and don’t have to wait to check email, headlines, etc. If I’m hurting my brand new laptop. I’d like to find out now and understand what’s harmful and how much off-time it needs. Thanks.

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    • Rich Menga February 15th, 2009 at 6:53 pm

      It’s a tight space inside a laptop and the heat from leaving it on all the time can cause premature hardware failure.

      If you want to leave a laptop on 24/7, consider a docking station or port replicator.

      http://www.google.com/search?q=laptop%20docking%20station

      If that doesn’t suit or you don’t feel like buying one, set the laptop to hibernate when the lid is shut. Yes it will take longer for it to “wake up” when turning it on afteward but it will extend the life of the unit.

      If you don’t feel like doing that, at bare minimum have the laptop monitor turn OFF after 10 minutes of idling.

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  3. angel san February 13th, 2009 at 11:15 pm

    I believe the computer can be turned on at all times when it is properly maintained. I use my computer more than 12 hours a day. If I am home, it will constantly run 24 hours. I only turn it off when I leave.

    My computer is 5 years old. The reason why it has not given up on me yet is because, I open it up and do my own cleaning. I frequently clean up parts on the motherboard and even remove the power plugs to check on the pins. The only problem I have is that my floppy drive and my cd writer no longer works. I have not added a new part ever since. The only changes I made are the accessories like mouse and sound system.

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  4. Bobhereyo February 13th, 2009 at 11:33 pm

    I would agree with your thinking about desktops and servers as well. I have a 9 year old Gateway server that used to be my main internet hosting server but for the past 6 years has been a print server in my office. That server has beeing running, knock on wood(press board?) for over 9 years now and the only time it was shut down is when I moved offices.

    Is there a Guiness Book of world records for longest running servers, desktops or laptops?

    Good post

    Bob in Pennsylvania

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  5. David M February 14th, 2009 at 12:21 am

    Its fine to leave a computer on all the time if you think that they are incapable of starting an electrical fire.

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    • Lespaul20 February 14th, 2009 at 1:41 pm

      I have never heard of a computer causing an electrical fire.

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  6. David M February 14th, 2009 at 3:05 pm

    http://www.thecrimson.com/article.aspx?ref=517485

    There are other examples of computer fires if you Google it.

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  7. David M February 14th, 2009 at 3:07 pm

    Ok…bad example…there are others.

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  8. Chris February 14th, 2009 at 4:50 pm

    What about the increase in electric bill, by leaving it on 24/7

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  9. Glen Ewell February 16th, 2009 at 11:07 pm

    Thanks for the tip. I have heard both sides but it just makes since to keep it spinning

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  10. Clint February 21st, 2009 at 11:55 am

    If you want your computer to last longer read up on Metal Migration / Electromigration.

    http://en.wikipedia.org/wiki/Metal_migration

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  11. Matt - Make Money Online March 8th, 2009 at 11:22 pm

    I use a macbook pro laptop and while I don’t leave it turned on all the time, often I need to as it is running different applications, batches and downloads.

    One thing I can say is that I probably only need to reboot it every 3-4 weeks, as I just put it into stand-by all the time. I never have significant problems at all by doing this either.

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  12. Clint March 9th, 2009 at 6:13 pm

    After getting an email informing me there was a new post to this thread I read it again and have decided to make a longer post.

    I own a computer repair business so run into this issue a lot with people. We work on name brand computers as well as build custom boxes. It never fails to amaze me when people think leaving a mechanical/electrical device on all the time is good for it.

    1. “Continually rotating parts in a computer are fans and hard drives (on the inside), and the most “grunt” needed is when they spin up from an absolute stop. When spinning they don’t have to work as hard.” and “It’s a good bet if you’ve ever seen a hard drive failure, it probably happened from a “cold” start, then the infamous “disk not found” message appeared.”

    While this is true most people do not start their computers up very many times a day. In my experience “disk not found” is as likely to happen on a reboot as it is on a cold boot.

    2. “Fans accumulate dust whether you want them to or not. This adds weight to the fan blades and can also dry out the bearing(s). If the fans stay spinning they will continue to do so almost indefinitely. However if they’re old and clogged up with dirt (including the dirt you can’t see or clean out), one day they simply won’t spin up from a cold start at all.”

    Fans accumulate dust because they are used. The more you have them on the most dust builds up on them and the more dust the pull into the computer through vents and cracks. Combat this with filters and blow the dust out of the case once in a while.

    Pretty much the only thing I can agree with in this article is that optical drives don’t spin while the computer is on unless they are being used. Otherwise … the primary reason all mechanical and electrical parts wear out is because they are used. So the more they are on the more wear and tear they get and the sooner they break. I have seen many identical machines where the only difference between them is how much they are left on. The computers that are turned off at night when they are not needed to perform a task always out last the ones left on all the time.

    If you really disagree try this. Buy or build two identical computers. Run one of them all the time and the other in the manor I suggest. When you replace the constantly left on computer you will change your mind.

    Or … do it with two radios or TV’s or two small desk fans … or anything you can afford to replace. Heck .. try it with two cars. Moving parts break because they have been moving. Electronic parts break because they have had electrons running through them.

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    • Peter January 2nd, 2010 at 9:25 pm

      It’s worth noting that every opinion stated here, while mostly educated, is anecdotal. So far, nobody’s got access to a nice, thousand-machine MTBF study, they just mostly believe what they believe because they believe it, including me.

      In general, I agree with the heat-and-moving-parts-kill machines view, given the following…

      I manage @24 desktops for a multi-location retail business. Over 5 years’ time, I’d have to say it’s a moot point, if only because:
      –often, function drives practice. Our main server HAS to run 24/7, so we gave it RAID 5 and daily cartridge backups, on the assumption that some key part WILL eventually fail. As my network wizard said, “A server is a five-year plan.” It gets taken down once a quarter for cleaning, once a year for firmware and other upgrades.
      –we have machines that are maintained and updated by suppliers, often in the wee hours. They run 24/7, but we tear them down every 2-3 months, blow out the heat sinks, and vacuum dust out of fans and power supplies.
      –we treat office and point-of-sale computers like you would a TV at home. You don’t turn it off when you run to the bathroom, but you don’t leave it on when you go to bed at night. I don’t turn my desktop off if I go out to lunch (though I do lock the terminal), but I shut it off at closing time. I like the daily reboot to reset everything, and I figure the power we save on 16 non-critical machines will cover the one unit and the few drives that fail before their 5+-year plan is up. They get opened and PM’d on the same more-or-less quarterly basis.

      All the best in the new year,
      Peter

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  13. hydraulic floor jacks March 14th, 2009 at 8:16 am

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        Reply

  14. Rick April 8th, 2009 at 12:49 pm

    I’m 59 and new at this copmuting stuff but i’d like to know if I turn off my laptop will my anti-virus run on schedule at 1am?

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  15. Carlito Castillo April 21st, 2009 at 5:54 pm

    A Desktop can be left turned on 24/7 but a laptop is not recommended due to possible overheating. I have a clients that has experienced overheating and motherboard going bad by leaving their laptops turned on 24/7. However, since you won’t be using it 24/7, keeping it running might just be a waste of electricity. So why not power it down when you’re not using it? Hope this helps.

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  16. Gerry -Refurbished laptops May 18th, 2009 at 11:34 pm

    One of the failure modes of electronic components and circuit boards is due to thermal cycling or going from hot to cold to hot. When a computer is left on all the time the failures due to thermal cycling are minimized. Fot this reason and some of the others listed in these posts I leave my computer powered up.

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  17. Tim.T June 15th, 2009 at 10:21 am

    Sometimes I turn the PC off; sometimes I leave it running for days. What this treatment is doing to my 2-year old high-spec dual-core machine I cannot tell, but it runs fine, purrs like a kitten. Never had any hardware issues thus far. This whole discussion reminds me of those big rocks you see in the desert which, over time, have split and broken apart because of eons of expanding in the daytime heat, and contracting in the night time cold. Eventually the rocks can’t take any more and fall apart. I suppose that happens to electrical devices, too, sooner or later. So while I am still not entirely comfortable with leaving it on for days, I think that might be the best option. I use a free little program called ‘SpeedFan’ to monitor all my fan speeds, hard drive temp, ambient and core temps – this helps me check to see if there’s any over-heating, and it also eases my mind a little.

    If you still want your PC to do something useful while it’s idle, get it to run one of the many apps out there like ClimatePrediction, SETI@home, World Community Grid programs, etc. You can set them to use as little or as much CPU power as you want, and your results will benefit all mankind!

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  18. Computo November 14th, 2009 at 2:40 am

    If you choose to leave your computer on all the time, It would be more safe to Not have it connected to the Internet. in my opinion, unless you run some type of business there is all most no point of leaving a computer running all the time. If the only reason you want leave your computer on 24/7 is because it starts up slow then you may want to consider upgrading the memory in it. Although not much for the average computer, they still use electricity so is it really worth keeping it on just because it starts up slow? The choose is yours.

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  19. Tech Tips November 23rd, 2009 at 2:11 am

    I agree that if its a desktop computer leave it on. If it is a laptop then turn it off at night. Besides the wear and tear issues, laptops just seem to get squirely (a tech term) when going in and out of sleep mode.

    With a desktop I still recommend rebooting it every day or two as this seems to help with stability.

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  20. JJM88 December 10th, 2009 at 12:13 am

    That last comment is right on. Laptops are considered portable anyway. They are built to be shutdown, or hibernated in between uses. In no way are they as efficient as a desktop considering there’s very little room for heat dissipation, and the parts are smaller, closer together, and generate much more heat anyway. The idea of the parts smouldering in their own heat after shutdown isn’t something that will do them in.

    Hibernation is the best compromise between a full shut down, and a quick boot. And of course it is recommended to do a restart now and then because when Hibernation occurs, sometimes drivers have to be restarted to work properly.

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  21. Rich October 11th, 2010 at 2:34 pm

    You’ve been reported as spam, you dumb fuckwit.

        Reply

  22. Khadi November 4th, 2013 at 10:11 am

    Wow! I’m not computer savvy, techi, computer literate or any of the other word(s) that can go along with this sentence. However, I really enjoyed reading all the comments. It must be so nice, to not have to be at the mercy of all the people and businesses with claims of being able to fix what ever ails your computer.
    Well, just wanted to say that I liked being privy to the conversations on this page.

        Reply

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