About half a year ago I bought a used UPS. It didn’t have enough output to power my main PC, but it’s perfect for my home server and network.
Starting on Christmas eve and continuing even today, my neighbourhood has been getting intermittent brownouts. It’s only affecting one phase (house is on a three-phase 240V connection), which happens to be the one powering my network (also all of the light fixtures, stupid Soviet house), and the UPS works beautifully. I didn’t lose any of my services even once. Without it, I would probably be reinstalling Proxmox and praying to the RAID gods to restore my hard drives.
“It pays for itself as soon as it is needed” is proven true once again.
When I lived in Pittsburgh we had daily brownouts, I lived in 3 different rentals in three different neighborhoods and almost every day my lights would dim then brighten. It killed so many cheap Walmart LEDs, but I never lost any computer equipment because I had a UPS for every device. I wouldn’t get them from the garbage room at the university, and occasionally buy them from thrift stores and replace the batteries.