When I'm staying home all day and want to periodically use the computer I will just leave the computer monitor on and only turn the computer monitor off when I'm going to bed.
If I'm using the computer and plan to be gone longer than an hour away from the computer like going to the store etc then I will turn the computer monitor off.
But if I'm only gonna be gone for 20 minutes or so then I just leave the computer monitor on.
Turning the computer monitor on and off constantly just puts more wear and tear on the computer monitors power button which can stop working easily so I just leave the computer monitor on most of the day and all day if I'm staying home.
These new led computer monitors don't even use $1.00 worth of electricity per month so It's not gonna break the bank leaving the computer monitor on.
The old CRT monitors used more power so were worth shutting off but the new LED monitors are best left on if you plan to use it within 1 hour.