Is it harmful for a mac in any way to never put it to sleep, or to turn it off?

I have a macbook air and an iMac that I set to never sleep in the settings. Only the displays go to sleep. I turn them off once a month. I am afraid that they could be damaged over time if I keep doing it. Could it happen?

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    Couldn't say for certain on MacBook/iMac but my old Mac Pro has been on for 7 years. It reboots for OS updates
    – Tetsujin
    Sep 13, 2015 at 10:24

3 Answers 3


You can safely leave your Mac powered on all the time.

Safe and Harmless

There is no practical damage or harm that will occur because the Mac is constantly running. Use your Mac as best suits your needs.

Restarting is helpful every so often – if only to install updates and clear out caches or temporary files.


As 1lann mentions, environmental factors like dust and heat build-up should be considered. Keep your Mac away from sources of dust, like limestone or sandstone walls, where the fans can draw in surprising amounts of particulate matter.

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    Everything in this post is entirely true. Please also note @1lann's answer because it addresses natural consequences of hardware use.
    – jsejcksn
    Sep 16, 2015 at 6:31

One way I can see potential damage is wear and tear of moving parts inside the computer, such as any hard disk drives and fans. Be aware that the fan may draw in a lot of dust if the computer is constantly running, and you may need to clean the inside of your computer at one point.


I administer a small network of Macs, servers and iOS devices and have been doing exactly the same thing for many years, I personally think (although can't confirm) that it adds longevity to the machine, I currently have a mac mini that is 8 years old running perfectly using this practice.

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