While there are many theories and if you ask 10 people you could get
10 different answers, here is my suggestion: do whichever you want as
it doesn’t really matter.

Pros to leaving it on:
1. Quick access anytime
2. Less wear and tear from turning components off and on (debatable)

Cons to leaving it on:
1. Wastes electricity
2. In the summer, the room is hotter
3. Have to wait for it to boot everytime

What do I do? I usually leave it on and only turn it off if it is
extremely hot, in electrical storms, or I will be gone for a few days.
Practically, it really doesn’t matter, so do whichever you prefer
(again, my opinion).