I used to feel like i had to put off my laptop every night… to give it some rest. But lately, i've been leaving it on for like a week at a time! It still works fine and it makes me wonder if and how often they really need to be absolutely shut down? How often do you shut yours down?

Answer:
Personal are not meant to be shut down at like the end of a day. You should only shut it down if your going on a long holiday. Because if it is a desktop or a laptop they both have a small battery in it. Everytime you restart the computer some power from the battery is taken away. Another reason is that small unknown changes happens. for example after sometime you’ll one day realise the cpu speed going up and down. To keep the computer at a good performing speed keep it switched on so it can reach a stabilised speed and will perform the extreme.
Answer:
it's good practice to close down system each time you are going away from system for long. As it will save battery power and electricity. secondly the chances of operating system crash will go down drastically as operating system (OS) can crash if OS gets restarted unexpectedly like in your case where you are keeping notebook turned on for days after days and chances of overheating increases as well as unexpected shutdown of OS.
Answer:
Why wouldn't you shut off your laptop? I shut it off each time I’m done using it. Saves battery power. Gives windows a opportunity to restart.

By saving battery power you’ve to recharge it less often and dont have to replace the battery as soon as you would otherwise.

Answer:
If you forgot to shut down your personal then set an alarm for shutting down the personal. By the help of this your personal will automatically shut down.