what is the max time you kept your PC on?

Checked my server, and it's been On for 18871 hours, 52 minutes.

No overheating yet.

You didn't specified if it's a desktop or laptop. A desktop has a bigger fan to help keep the CPU cool. Conversely, a laptop has a smaller fan to cool the said CPU.

Now, today's computer can withstand more than a decade ago. If the computer is on and not active,it will go into a screen saver mode or standby until a key is pressed, that depends on the setting you have on it. I kept my laptop on for eight hours and no problem. Just don't open to many program.

I leave mine on most of the time, and let it go into standby which is pretty much off. Saves lots of time. I haven't actually turned it off for a couple weeks now, But if i leave for a trip or something i shut it off. I have no heat problems and my computer is six years old. (updated frequently)

The whole day. In my opinion, my PC isn't the best for cooling, but it runs at normal temps. I ran it at idle for most of the time, using it on and off.

I know this is bad, but I have left my computer on for months without turning it off...

i can keep mine on for a couple of hours but i have to place it on its side every 45 minutes or it does over heat easily.

couple weeks. i would just get new fans. and if sound is an option get liquid cooling. expensive but very efficient and dead quiet

lol Idk I keep my computer on for days months idk i don't usually shut it off I haven't had any problems and I've had it for a few years i mean i bought it for 200 dollars but keeping it on all the time hasn't do anything to screw it up