I usually do not power off my computer but put it in sleep mode or hibernate.
The best thing about this is you have all your software opend and you do not need to stay much time to see what you were doing before you stopped working.
But on my workstation i just reinstalled my Windows and in the morning i always find my PC already on. What can you do to fix this issue?
Simple: you just need to run the bellow command:
powercfg -devicequery wake_armed
Anfter you have run this command you will see a list of devices that wakes up your PC.
You need then to go to Device manager, find those devices and unselect the option from Power Management: Allow this device to wake the computer.
After you have finished the list you can run again the command to see if the result is NONE. If that is the case then you are done:)