I've been using Macs since 1987.
I ALWAYS shut down my Macs at night. I can count the number of times they've been left running on my fingers (due to long file downloads).
I will also shut them down during the day if I'm going to be away for a while. For example, I'll shut down my desktop Mini if I'm going to be out of the house for a few hours -- I don't like leaving much of "anything electrical" running when I'm not there (exceptions for things like refrigerator and furnace).
I'll leave my MacBook Pro sleeping during the day, but again, WILL shut it down each and every night.
Welcome to days of yore!
I first used Macs in 1985. The norm back then was to shut down any computer when we finished using it, and switched off or unplugged at the socket. That remained standard practice for many years, so when I bought my first Mac Mini in 2005, I continued to do the same. However, it had to be left off for an increasingly long amount of time before it would successfully boot again. Then I noticed in the handbook Apple advised it should be put to sleep if you were going to be away less than a few days, so I started leaving it on.
The same advice was given in the handbook for my second Mac Mini, the early 2009 iteration.
Nowadays many, if not most, people leave computers (and other appliances) on 24/7. With sleep modes available, power consumption is minimal, and it is reckoned to reduce wear and tear from starting up. Surge protection is available to prevent damage to vulnerable electronics in the event of unstable mains supply.
Since 2009 I have used a voltage regulated UPS with my Mac Mini. The one I have now is monitored by the computer, which I have set to shut down if the power is out longer than 10 minutes.