It took some of us a long time to realise that, unlike many hobby machine tools, the PC is designed with a 100% duty cycle, i.e. they are meant to be permanently powered up. Mine wakes from sleep mode every night around 4am and updates some of its parts. The only way to discover this is by viewing the system log since it does not list these mini-updates.
If it is powered off at night these updates take place after you switch on . . . which may be fine if you are on "superfast" broadband, but can involve a very long tea-break if you are on a slow rural 'phone line as they hog ALL the bandwidth 
Many of the bigger updates involve a long-winded reboot but if you have Win10 Pro you are allowed some leeway to choose when to do this.
Mike.
All computers are a pain, but sadly they are no longer optional unless you are a hermit who does not need to contact anyone in the outside world for business or social purposes . . .
Edited By Farmboy on 12/04/2018 23:00:09