I shutdown my laptop before putting it into my messenger back to take home. Prevents overheating. Most (if not all) OSs allow you to restore your previous session when you power back up - so you don't have to restart all your applications and documents. And machines these days start up in few seconds.
I shut down my dev machine at work because it uses Windows, and it's not safe to leave Windows running overnight due to its insane update system.<p>I don't run Windows machines at home, and so only shut down those that I don't use on a regular basis.
My Desktop machine runs 24/7.<p>It also acts as a server, so it does a lot of work overnight while I'm asleep. (Daily backups, other routine tasks like cleaning all the crap that accumulates during the day, etc.)<p>My Laptop runs when required. It takes a whole 15 seconds to boot up from scratch. Then it gets turned off. The laptop is a Desktop alternative, rather a main machine in its own right.<p>Oh. And the Raspberry Pi? It also runs 24/7 solely as my website server.
There <i>will</i> be problems on Linux after some updates if you don't reboot, so I reboot when updating like on Windows.<p>So you're supposed to at least reboot.