I think I understand the main differences between Power Off, Restart, Log Off, Suspend and Lock, but I might be confused over the nuances and the best time to use each one.
My question is: Which one of these 5 would be the best one to use overnight while my computer is not in use?
(I'm running with OS 18.1, have a desktop not a laptop, use a wired connection not WiFi, turn off the modem at night, rarely ever Power Off and only Restart after an update or freeze.)
I would says suspend if your computer wake up without problem after, you just have to test, and if you computer do nothing overnight my choice will be shutdown...
I always Power Off when not used for many hours e.g. overnight. Then you start with a clean boot next day. That assumes you do not have apps that you run continuously in the background when not actively sitting in front of and "using" the machine.
Well, when it is overnight, I would say Power off. Then Your Machine is off and doesn't need unneccessarily consume Power.
The "Power Off" would be the best option. It puts less stress on your computer and it's components.
There is another setting that is missing and that is Hibernation.
I never use Suspend or Hibernation for my needs. Rarely I use Lock as well.
Hello,
According to my research into hibernation, the wider Linux community considers this feature to be unreliable and disables it by default.
Here is a discussion thread from 2025 that I found on the forum:
Agreed 
and great call as well as linked topic. 
I edited my post to remove article as I don't want to stir novice users to install.
I checked, but I can't find a "Hibernation" option.
That is correct. It's disabled in Linux by default because it can cause system issues.
I believe you have to have a /swap partition to use Hibernate. But yes, Hibernation is considered problematic.
I usually put the thing to sleep when away for a few hours and turn off when I am done with it for the day, nothing like a fresh boot and coffee in the morning.
David