I use the "sleep" mode and disable hibernate since hibernate will consume some HHD space by saving RAM info to the HHD, since I have a SSD (Solid state drive) as my main drive, I don't want a bunch of re-writes.
I shut mine down at the end of the day, Sometimes when programs close, they don't close down properly, or 100% and use resources. You also have memory leaks that use up resources. Reboot will clear out those resources and give you a fresh start.
But that is for me and my desktop, We have a few work PC's that are hardly ever off unless rebooted to "clear 'em out" or the power goes out, so everything is backed up at the end of the day.