There is no reason to even shut it off. I've been using Mac minis since the first model came out, I must be on my third or fourth and getting ready to buy an M1... and I have run them 24/7 for most of the last fifteen years. I'm running two right now, one sitting in the corner as a server.
I can see my main one has been up for
18:45 up 36 days, 5:37, 9 users, load averages: 2.94 3.41 4.47
and I just rebooted the server recently
18:45 up 7 days, 3:37, 2 users, load averages: 3.08 3.22 3.24
The one thing in the older models that might have the most potential to wear out is the hard drive, or perhaps the fan, but today's hard drives are SSD and from what I've seen online, the fan barely runs.
Of course, you can if you want to - to conserve energy, or if your local power is inconsistent and you're concerned about power spikes. For the former, just set your Energy Savings so it goes to sleep which should shut down the monitor automatically, and for the latter... if you're that worried, what about when you're using it? You'd want a UPS or good surge protector for that.