Is leaving laptop on overnight bad?

My computer is in use most of the day. Will a laptop handle being on for so many hours every day?

Yes. Mine are typically on 24 hours a day, seven days a week.

However, there are trade-offs to leaving your laptop running all the time.

It all comes down to battery life

The way to keep a laptop running at all times is to leave it plugged in and never shut it down. The battery never runs down, so the laptop never needs to shut down on its own.

The issue is that the battery never runs down. In fact, the battery rarely dips below 99% of its charge.

By itself, this isn’t a problem. Your computer and your battery will continue to operate just fine. However, you may find out that when you run it on battery only that 100% charge doesn’t last as long as it used to.

By leaving your laptop plugged in all the time, you’re making a decision to shorten the battery’s life: both the amount of time you can run your computer when not plugged in and the battery’s usable life before you need to replace it.

Batteries die

All batteries die. They lose their ability to hold a charge — or as much of a charge — and they become less and less useful to power the laptop. On my oldest laptops, for example, the battery acts as nothing more than a glorified UPS and can keep the machine running for only a few minutes.

How quickly a battery dies is a function of its technology and how it’s treated. The ideal treatment for most is something along the lines of:

• Keep it ~80% charged if you can.
• Use it down to the 10% range.
• Use a charger that is matched specifically for the battery.
• Don’t let it get too hot or too cold.

There is much controversy around the specifics of that list, so don’t take it as gospel by any means. The specifics also vary dramatically based on the battery type, how it was built, and even the software that controls how it gets charged.

One thing most people agree on, though, is that keeping the battery 100% charged at all times is generally not ideal. It’s not disastrous, and your battery generally won’t die quickly — it’ll just die somewhat more quickly than if you’d treated it differently.

The pace of technology

I leave my laptops on 24×7 so as to keep them automatically updated and run backups and other scripts at night, when they’re not in use. It’s a choice I make.

What I’ve found is that by the time I care about the battery life being too short, the laptop itself has probably fallen into disuse by virtue of having become “old technology” in comparison to newer machines. In other words, the battery’s lifespan still exceeds the laptop’s useful lifespan for me.

In at least one case, I was able to extend the life of one of my older laptops by replacing the battery before I loaned it to a friend with less extensive computing needs.

As I said, it also varies dramatically based on the manufacturer. My MacBook’s battery lasted much longer than I expected and is probably outliving the equivalent configuration in other machines.

My sense is it’s not something to spend a lot of time worrying about. Use the computer in a way that makes the most sense for your needs.

• Turn it on occasionally — long enough to do whatever — with occasionally lengthier times to allow it to update. Plug it in when the battery gets low.
• Turn it on in the morning, turn it off at night. Travel with it as needed. Plug it in when not traveling.
• Or you can be like me, and leave it plugged in and running day and night, taking it for travel occasionally.

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It's been one of the most long-running discussions in computing: is leaving your PC or laptop on overnight bad, or should you always turn it off?

There are actually some pretty solid arguments for either approach, meaning the answer depends on how you use and how much you use the computer. Let's take a look at some of the pros and cons.

Why You Should Leave Your Computer on All the Time

There are several good reasons why you should always leave your PC on overnight. It's not just about being quicker to get started, but it can enhance your computer's functionality.

1. It's More Convenient

The main reason why you'd want to leave your computer on is for convenience. Rather than having to wait for it to boot, it's always ready to go.

A typical system with an SSD will take up to 30 seconds to boot into the operating system—and it could be up to a minute or more on an older machine with a hard drive. If you have a large number of programs that are set to launch on boot, it'll all take longer.

Leaving the computer on bypasses this problem. Awakening your PC from Sleep mode will take just a couple of seconds, and all your previously launched apps will also still be running.

Related: How to Fix Windows 10 Sleep Mode Issues

2. Your Computer Will Stay Up to Date

There are numerous tasks that are essential to maintaining your computer and data. Almost all of them are better off being performed overnight.

Installing operating system updates, creating backups, running virus scans, or uploading large amounts of data, such as moving your music or photo collection to the cloud, all take some time and use varying amounts of system resources and bandwidth.

Leaving them to run while you're away from your computer or even scheduling them to happen at night will keep you fully up to date without interfering with any other work you are doing.

3. You'll Always Have Access to It

Having your computer turned on all the time enables you to run certain pieces of software that would otherwise be off-limits.

This includes remote access software, such as Remote Desktop in Windows. You'll never have to experience the frustration of leaving an important file on your desktop at home. You can just log in remotely on your phone, tablet, or work computer and grab whatever you need.

Why It's Bad to Leave Your Computer on All the Time

But does leaving your computer on damage it? You probably turn all of your other devices off when you've finished using them, and here are five good reasons why you should do the same with your PC.

1. Every Component Has a Limited Lifespan

It's a simple fact that all hardware has a finite lifespan.

A monitor's backlight is typically rated for a lifespan in the tens of thousands of hours. A laptop battery's capacity will noticeably shorten with as few as 300 charge cycles, while some SSDs are only good for around 3000 program/erase cycles (although in many cases they're much higher).

In reality, you're likely to have upgraded your computer long before you hit any of these limits. But by leaving your computer on you are putting it under constant stress, albeit a small one. It's also generating heat, which is one of the biggest factors in reducing your hardware's lifespan.

2. It Wastes Power

It goes without saying that leaving something turned on when you aren't using it is a waste of energy. But how much?

A 13-inch MacBook Air from 2018 has been measured as using up to 25 watts in moderate use. This drops to 8W when idle, and in Sleep mode, it plummets to just 0.3W.

So, there's a massive difference between the power consumption of a computer that is active, idle, and sleeping. Turning the monitor off saves a large amount of power, and putting it into Sleep mode saves even more. However, in Sleep mode, you'll lose many of the benefits of leaving the computer on, such as being able to access it remotely.

You should also note that a computer turned off but still plugged in will continue to use around a small amount of power. So if you do want to reduce how much power your PC uses, be sure to pull the plug after you turn it off.

3. It Won't Be at Risk From Power Surges and Cuts

A power surge or power cut is a relatively rare but very easy way of damaging a computer.

Power surges are most often thought of as relating to lightning strikes, but they can also be caused by high-power household appliances such as fridges. If the surge is great enough, it can cause damage to any electrical items, not least the sensitive components in a computer.

You can guard against this by plugging the PC into a surge protector. These are recommended for general use anyway, but even more so if you plan to leave your computer on all the time.

4. Reboots Improve Performance

Does leaving your computer on slow it down? Back in the day, regular reboots were an integral part of a computer user's life, just to stop the machine from grinding to a halt.

This is no longer the case. Modern operating systems are very adept at managing resources, and if you choose never to turn the PC off you won't notice too much degradation of performance.

However, a reboot is still the most effective way of solving many of the day-to-day errors you'll encounter. Whether it is an app that is crashing or a printer that has stopped working, a quick restart will often fix it.

Turning your computer off at the end of the day flushes the system and ensures you will start fresh and, hopefully, bug-free the following morning.

5. It's Quieter

Finally, depending on where you keep your computer, you might want to turn it off simply because it is quieter. You can silence the alerts and notifications easily enough, but you'll still have the ambient noise from the fan and the clicking hard drive to contend with.

Naturally, this won't be an issue with a modern, fanless laptop sporting a low-power CPU and SSD. But for a more traditional desktop system, switching it off is the way to a peaceful life.

Is It OK to Leave Your Computer on All the Time?

There's no point turning your computer on and off several times a day, and there's no harm in leaving it on overnight to run a full virus scan either. A computer will also benefit from being rebooted from time to time, and in the height of summer, it's a good idea to give it a chance to cool down properly.

So, should you leave your PC on or turn it off? Ultimately, it depends on your needs. If you're going a few days without using it, then by all means power it down. But if you need it to be up and ready to go at all times, there's little harm in leaving it on for as long as you need it.