I leave my production systems (1x NAS/1x Proxmox Host) on 24/7 and shut down test systems or my onside backup. I do it mainly to save some power and also noise, because all servers are in my office room. I would prefere some low power/noise machines that can keep running 24/7 and if you really need some horse power because you would want to test something or play around, you can power it on and shut down whenever you want.

But I dont use any UPS, because the power grid is very stable where I live but I have snapshots every hour or so. I can live with an hour of data loss if shit hits the fan.