I leave my desktop computers on all the time and only shut them off or restart them when needed.
If I'm going away from home for a week or more then I turn the computers off.
However if I'm only going to be gone for a day or two then I leave the computers on so that they can update overnight and I also download and upload files overnight as well.
It's much harder on the desktop computer to turn it off and turn it back on again everyday and every night.
I only notice an increase of about $10.00 per month on my electric bill when leaving my 2 desktop computers on all the time.
It's not worth the hassle of turning them on and off and waiting for them to boot back up and having to load every program back up.
I work from home so it's needed that I can just get onto the computer in the morning and go right back to work and not have to wait for the programs to load and for the computer to boot up.
A laptop computer could overheat too much if left on all the time but for a desktop computer it will be just fine.