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Computer longevity from turning it off or leaving it on is a question without a real consensus of opinion. Not dropping it is really the best plan!

I searched your site and those of your associates and didn't find my answer. In your opinion, which will extend the life of the hard drive of a computer the longest: leaving it on or putting it to sleep or something else?

In this excerpt from Answercast #77, I look at the wear and tear that happens to a computer over time from shutting it down, going to hibernate or standby, or simply leaving it running.

Computer longevity

The short answer is, "It depends."

Ultimately, I don't really see a whole a lot of difference between the three in the terms of lifespan.

In the case of a portable computer, how you carry it around is probably the biggest indicator of lifespan. As long as you're not banging it on walls or that kind of thing while the thing is running - that's one great way to increase the lifespan of your computer. But in terms of shutting things down, or turning things off, leaving them running, or using hibernate? In my opinion, it just doesn't make that big of a difference.

Now, I know there are going to be people who are going to be absolutely convinced that one solution or the other is absolutely what you have to do. But, once again, it's a case of: since there are so many diverging opinions, there are so many diverging priorities, that ultimately indicates to me that there is no strong consensus on the issue at all.

Everything causes wear and tear

I mean the issue here is: when you leave something running, well, it's running. It's staying hot. The drive may keep spinning, those kinds of things. You know, yep - that will eventually wear on the computer.

On the other hand, shutting down, regardless of how you do it (shutting it down by powering it off; shutting it down with standby; shutting it down with hibernate), they're all more or less the same from a hardware perspective.

That means that the drive and the circuitry all cools down and it stops spinning - but here's the problem: cooling it down and heating it up, and cooling it down and heating it up, and cooling it down and heating it up? That too stresses the hardware. It stresses it in a different way, but it does, in fact, cause wear on the hardware.

So the computer is ongoing to die one way or another. I guess you're kind of choosing your poison.

Ultimately, I leave almost all of my machines on 24 hours a day. That's just me. It's the way I run my system. I have systems actually that rely on my computers being up 24 hours a day (mostly dealing with backup and a few other things.)

Other people are absolutely convinced that they need to turn their computer off every day so as to conserve power - that's great. The concern here that I want to be very clear about is I don't believe (and I really don't want you to walk away with a real, strong feeling) that one or another reduces the wear on the computer overall.

It doesn't in my opinion. In my opinion, all it really does is it changes the kind of wear that your computer is under going.

Leave it in the box!

The only way to make your computer last longer in terms of wear is to never to turn it on at all! Unfortunately, that doesn't make it very useful - and even then, it's still going to not work after awhile because there are components that literally wear out over time.

So, ultimately, it's not something that I would spend a lot of effort and concern on. I would choose whatever model, whatever approach (turning the computer off, or on, or leaving it running) that works best for you; that is most convenient for you; that works the best with how you use your computer and how your computer is a part of your day-to-day activities.

(Transcript lightly edited for readability.)

End of Answercast #77 Back to - Audio Segment

Article C6122 - December 10, 2012 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Larry Emmons
December 11, 2012 8:26 AM

I agree with you except for brand new machines right out of the box. I think they should be left on 24/7 (Burn-In Time) during the warranty period to find any problems sooner than later.

December 11, 2012 8:55 AM

I think it depends a bit on your user habits. If you use a computer every day, I don't see any advantage in turning it off. If you only use it once week, I'd probably turn it off.

Personally, I don't like to wait on a computer. So I tend to leave it running.

Ron Hoover
December 11, 2012 8:56 AM

My experiance is that in a factory computers are left on 24/7 50 weeks of the year
During shut down they are turned off. On power up there are always some failures. Maybe in the range of 2-3%. Mostly just commercial white boxes. they also die during normal use but if all are shut off they always seems to be failures on start up. Of course some of these systems are 5-8 years old by the time they die.

Marty W
December 11, 2012 9:23 AM

But what about recommended program updates that require a computer restart to take effect. If you leave the computer on 24 hours a day you may not be engaging program updates.

December 11, 2012 9:26 AM

In my experience, laptop battery, power supply and fans wear out faster if you leave machines on.

Tom R.
December 11, 2012 9:28 AM

I never turn off my desktop computer if I can help it. There's something wrong with the RAM that when the hardware cools down to room temp it becomes very hard to restart the system. I have to turn it on/turn it off over a dozen times before the BIOS starts running. As long as I keep it running I have no problems at all.

Mark J
December 11, 2012 12:31 PM

I've also read that not turning your computer on is the best prevention against viruses ;-)

Texas Mike
December 11, 2012 1:02 PM

As an electrical engineer for nearly 40 years, I have to entirely concur with Leo. Neither one is the ideal solution; there are pros and cons to both. To reiterate, both will wear down your computer, just in different ways. In my (and most engineers') experience, MOST failures occur during power-up and power-down. Most, not all. Parts do still wear out even while running.

If you only use your computer for an hour a day, shutting it down is probably the best way to prevent wear, but no guarantee. Remember, powerdown and powerup can be a problem, but that's just the luck of the dice. If you use your computer 12 hours a day, you won't see any improvement in wear and tear by shutting it down for a few hours.

Me, I'm working with my computer all day and all night long. Often my computer is working on something even when I'm not there. I have not turned off my computer in years. Well, not exactly true. When updates demand that I restart, then I do so. And there have been times that a cold reboot has been necessary.

The point is that my computers have lasted for years while constantly running. And shutting them down momentarily has not decreased their life expectancy by any measurable value. Really, it's not so different than cars or trucks that run hundreds of miles a day. But those that are only used to go to the store once a day are not left running.

Mark J
December 11, 2012 1:37 PM

Any program updates which require a restart, will notify you of this and ask you if you want to restart the computer. In that case, you would restart it as soon as it is convenient for you.

December 11, 2012 3:22 PM

Several years ago, I read that Windows has a counter that maxes out after about 6 months, causing a crash. Is this just an urban legend, or if true has it been fixed?

That's one HECK of an urban legend / conspiracy theory. While it might be unusual for Windows to stay up that long, it's not because there's some artificial counter to force it.

Mark J
December 11, 2012 4:10 PM

That one's an urban legend.

December 11, 2012 5:05 PM

I'm the hedge-your-bets type. Since I've never seen a definitive answer, I leave my computers on some nights and turn them off, or put them on standby, other nights. I do kind of like the idea of one of the posts here to run a new computer 24/7 (let it fail before the warranty expires).

December 11, 2012 6:06 PM

What about hackers doesn't leaving it on give them more time to do their dirty deeds .

No more so than having it on while using it. If powering off is important for your computer's security then you don't have appropriate security in place.

December 11, 2012 9:21 PM

Excellent advice Leo. There is one exception however that should always be respected, especially for lap tops. Do not move your system while the disk is spinning. A slight mishap could cause many application problems due to the read/write heads scratching the surface and damaging files, or worse make the disk completely unreadable by affecting the file system managing the disk. Always power off to move a system, even laptops!

Jack @ Finland
December 11, 2012 10:23 PM


You briefly mentioned temperature but missed the main factor affecting the life-time of computers: The temperature of the hardware.

Quite typically, computer hardware does not break due to wear alone. It breaks due to temperature-accelerated wear. It can be mechanic wear (e.g. fans, HDs) or electric/electronic wear (e.g. capacitors, even the CPU if not cooled properly).

The accelerating effect of higher temperatures can be modeled pretty well (for the purpose of life-time estimation) by the Arrhenius Equation (see ).

For every increase of temperature by 10°C or 18°F above the nominal cuts the equipment life-time roughly to half of the original. So, if the temperature inside the computer case is 40°C, you can expect it last only 1/4 of a computer having a case temperature of 20°C.

So, the most important factor affecting computer life-time (IMHO) is the case internal temperature. If the case is not properly ventilated, it's like "calling for an accident".

December 12, 2012 2:47 AM

I leave my work PC on 24/7. One reason is so it can do a thorough virus scan over the weekend (and yes, it does take a weekend - last week's scan took almost 60 hours) and the other reason is not to lose 15mins a day waiting for it to start up.
At home, I switch off. I'm only using the PC for a couple of hours a night, so don't see the benefit of it running while i'm (a) at work, or (b) asleep.

PC Medic
December 12, 2012 10:26 AM

if the question was framed like this:
What is best not only for the life of the machine but for the user experience - both in the short and long term?
The answer falls to the side of turning it off at the end of the working day. My reasoning follows:
1. Windows XP, Vista and yes even Win7 (but not as much) don't like to be left on continuously. Anyone who's had to restart their machine because of some weird thing that didn't work right or some other uncooperative PC behavior, knows that this simple act will fix a myriad problems. Now we can wait for problems like this to arise before we shutdown but in my 14 year career of fixing computer problems, I've seen many a self inflicted problem caused by the various troubleshooting efforts people will attempt when trying to resolve problems that could be fixed by simply restarting the computer.
2. Power outages while the PC is running is one of the most common ways to screw-up a hard drive. Therefore: The more time the PC is left on the higher the likelihood of such a mishap. Why then leave it on if it's not needed.
3. The more time a PC is left on, the more dust and pet hair, etc is sucked into the machine. More dust equals shorter PC life.

Now, when I'm on, I can usually come up with more reasons and some of those have been brought up already but to my mind these 3 are enough to convince me that off is better than on and that getting into a simple habit of shutting down before bedtime is the prudent way to go.

Michael S
December 12, 2012 7:07 PM

My opinion with Laptops, is that if you're moving it, hibernate / sleep / off are a must! Even if you're not "banging it on walls", etc. :)

I do recall one period working on a project in the office that involved moving between desk and meeting room with my laptop through the day. I wasn't thinking much about the laptop, and I was leaving it running as I ran back and forth - bad move. I wasn't careless with it, and certainly didn't bang it about, but within weeks of the project finishing (and thank goodness it was AFTER), the hard disk began to show clear signs of failing. This was a BIG lesson for me.

In the same situation, I now send it to sleep.

And yes Leo - I had backups. :) (Too paranoid not to.)

December 13, 2012 2:43 PM

It's true that thermal cycles cause wear. But that varies greatly from computer to computer. Some chips are pushed hard and may not be well cooled, to they run very hot. My previous laptop, a high-end Dell XPS-15, ran extremely hot and would blister your leg. I joked that it was really a high tech hot plate. Its huge thermal swings cooked all the components and eventually killed the motherboard, so leaving it on probably had more downside than turning it off. My new Lenovo ThinkPad has an i5 chip that's not pushed and is also well cooled. As a result the Lenovo feels as cool as any other surface in the room so I choose to turn it off or put in Sleep mode when not in use. Modern hard drives are incredibly reliable and have great longevity, so the first thing to go on a PC that's left on continuously is usually the cooling fan, which only has so many revs of lifetime. Some find their PC gets cranky if not rebooted regularly. Even my dual processor Droid phone requires a reboot about once a week to keep it happy. But the most important "power" issue is not to turn off or leave on. Instead, it's the importance of providing clean, uninterrupted power. All of my PC's have a combination UPS-PowerConditioner to clip voltage spikes and permit graceful PC shutdown when utility power fails. The latter is done automatically, using software that comes with the UPS.

Tom E
December 15, 2012 4:14 PM

Most electronic devices suffer by warming up and then cooling down. I have always adopted the policy of leaving the computer on if you are coming back in an hour, otherwise turn it off.

bob price
December 28, 2012 5:09 PM

There is perhaps no issue that has been debated more, and will continue, as the correct answer is, "It depends."

I can only speak from the experience as a factory manager for several large companies over many years. The failure rate of computers that were shut down every night and restarted in the morning was double those that remained on.

December 29, 2012 1:26 PM

For the past 30-odd years, I have always switched off my computers if I will be away from them for longer than a few hours and certainly overnight. I realise that probably 70-90 per cent of Ask Leo readers are North Americans and that this would therefore probably go straight over their heads [the more so in this golden dawn of shale gas], but there are actually sound socio-ecological reasons for being attuned to consumption of resources and energy and for not despairing but applying the lessons one learns. And for theose who may want to point out the consumption surge involved in switching on and off (that's "powering up and down" or whatever) I do take thiose calculations into account in budgeting my energy and resource consumption. [PS. My computer use isn't unique. Every thing I do I assess in the same light. For instance, I don't use a fridge (yes, it's entirely possible and, again, not a "false economy" - no "driving to the refrigerating shop every day" for me), maximum of one toilet flush per day, decry urinals, promote dry urinals, etc. One meat-free day per week by every household in the developed world (or one extra if you already do) would make a MASSIVE difference to energy consumption entailed in the meat supply chain, etc. etc. It's all there to be found out.]

December 30, 2012 1:50 PM

one part of the problem has been touched on, heat cycling. The expansion and contraction of parts due to heating. Unfortunately materials expand at different rates. Back in the early days of computing there was a common problem related to heat cycling. Chips would "creep" out of their sockets. Simply pressing them back in place would fix the problem.

That has not been a serious issue for many years now.

January 21, 2013 5:13 PM

"Depends" is exactly the right answer. Some hardware are made more durable.
On my old desktop, it'd have trouble trying to put it to sleep (or was it hibernate)? On Win 7 with my newer desktop, it COULD go to sleep, but sometimes I'd leave it on out of forgetfulness, laziness, or for it to run a program/diagnostic while I was away. I put my laptop to hibernate/sleep so the screen isn't on the whole time.

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