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I have a Mac mini M1, I usually use it at night, and shutdown it before I go to sleep. I go to work in the morning, and will use the Mac again at the night.

After every shutdown, I unplug the power cord because I guess it will affect something bad to my Mac if I leave it plugged, am I right and is it necessary?

And should I sleep the Mac instead of shutdown?

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  • 22
    I had a Mac that never even slept for over 10 years, it was always on, always available. It only ever rebooted for OS updates. They're built to last.
    – Tetsujin
    Sep 3 at 16:14
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    @Tetsujin Counter-point: G4 Cube.
    – Dai
    Sep 5 at 0:38
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    I am curious why you think that it would be bad for it to leave it plugged in (or even running). Sep 5 at 4:58
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    Do you disconnect the power cord from the mains or do you disconnect it from the plug socket at the back of your Mac? Because if you are doing the latter, the wear and tear on the connector is probably a larger factor on the lifetime of your Mac than anyway of leaving it on at night Sep 5 at 7:09
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    @Messi Electricity is a lot like water. Turning off your computer is like turning off a faucet. The water will stop flowing, even though the faucet's still "plugged in" to the pipes. Turning off your computer is the same as turning off the faucet, it won't take any more electricity (ignoring tiny amounts of power for, e.g., a light on the power button). Sep 6 at 0:09
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While there are many opinions on what you should do and when you should do it there is no technical reason why you need to unplug your Mac when shutting it down at night. In fact you don't even need to shut it down at all.

I have a Mac Mini that is attached to my main TV. It stays on all the time. I have a MBP that I never do anything more than shut the lid and let macOS decide what to do (usually just sleep/hibernate).

The only reason I can see to unplug your Mac would be that you have a lot of issues with power in your area. In other words there are frequent lightning strikes, the power coming into your place is "dirty" (EG it varies a lot in voltage, there are spikes and dips that could damage anything plugged into your place's power).

And note that the average household has a lot of devices with computers in them (TVs, Microwave ovens, video game consoles, smart home devices, etc.)that are always plugged into power. If they have not been damaged by the power in your place it is unlikely that your Mac will.

Me, I'd leave it plugged in and then either sleep it or shut it down, whichever you prefer. It won't hurt to unplug it but (excepting the issues I just outlined) it also is unlikely to hurt to leave it plugged in.

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    Yeah. I've had Mac Minis since 2012, and I leave them permanently on all the time. Shut it down if you want, but there is no firm need to remove the cable.
    – benwiggy
    Sep 3 at 16:12
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    I have a mac mini used for tv stuff, it shuts down at 1AM and reboots at 06.00, and set for auto update. Only time that does not shutdown is if I am watching a late film…
    – Solar Mike
    Sep 3 at 20:56
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    If your area is prone to things like lightning strikes, you can also buy surge protecting power strips that you can plug in between the wall power and your mac so that in the event lightning or some other event creates a power surge, your power strip will likely be the first thing to die, protecting the mac. If you want to go really overkill, its also possible to get uninterruptable power supply (UPS) units that can "condition" the power for you to smooth out any "dirty" power that your area might have. they may also sell power conditioning units as separate, less-overkill devices Sep 5 at 0:50
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    @DeveloperACE is correct just be aware that if a power surge or lightning strike is near enough it will fry anything plugged into anything, and some things not even plugged in...FWIW Sep 5 at 15:04
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    @benwiggy Rockin' a late-2010 Mac Mini here! It started life as the 'Server' model, has had an SSD upgrade, still (just about) chugs along as my media server. Current uptime: 96 days. I'll be sad the day I have to replace it.
    – John Noble
    Sep 6 at 7:16
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As a general rule, you don't need to unplug your computer if your electrical installation and power supply provide power which complies with standard power quality rules.

However, if you have low power quality in your home or office (i.e., grounding is not appropriate, or there are frequent surges and/or dips in power -- that you could see as sudden changes in the intensity of your office lights, for instance), it is advisable that you do this while you are not using your computer. That also removes the small amount of power that will be consumed by the computer to allow for it to be quickly started up.

But if you are indeed concerned with power quality, you should probably look into buying an UPS, to avoid issues with electricity affecting your computer.

Incidentally, if you are really using your computer only at given hours, and you leave it connected, you can program your Mac so that it shuts down or starts up at a time of your choosing.

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  • How would one know that one had 'low power quality'? I just feel that this answer seeds doubt, and have down-voted it. The vast majority of people do not have low power quality and should not unplug anything at night.
    – John Noble
    Sep 6 at 7:14
  • I see your point, @John Noble, I've done an edit that tries to clarify that, because I agree with you that seeding doubt is not a good thing. But there are areas in many places which have low power quality, with either improper grounding (80% of the low power quality issues are related to that, per the Palo Alto Electric Power Research Institute), or issues with power generation.
    – juandesant
    Sep 6 at 15:12
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    @JohnNoble Having seen electronical equipment fried by lightning, unplugging may be wise in areas/seasons with a lot of thunderstorms (and of course, as the answer already mentions, in areas where power is sometimes unstable).
    – nohillside
    Sep 6 at 15:42
  • @John If you see incandescent lights dim quite frequently (every day or more), I’d say your electricity is “low quality” and a UPS would be a good idea.
    – Cole Tobin
    Sep 8 at 19:27
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There is no reason to even shut it off. I've been using Mac minis since the first model came out, I must be on my third or fourth and getting ready to buy an M1... and I have run them 24/7 for most of the last fifteen years. I'm running two right now, one sitting in the corner as a server.

I can see my main one has been up for

18:45  up 36 days,  5:37, 9 users, load averages: 2.94 3.41 4.47

and I just rebooted the server recently

18:45  up 7 days,  3:37, 2 users, load averages: 3.08 3.22 3.24

The one thing in the older models that might have the most potential to wear out is the hard drive, or perhaps the fan, but today's hard drives are SSD and from what I've seen online, the fan barely runs.

Of course, you can if you want to - to conserve energy, or if your local power is inconsistent and you're concerned about power spikes. For the former, just set your Energy Savings so it goes to sleep which should shut down the monitor automatically, and for the latter... if you're that worried, what about when you're using it? You'd want a UPS or good surge protector for that.

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