I have 2 UPS’s, a small one that runs the fibre gear and keeps the connection alive and the main one in the rack that keeps the main server running for a couple of hours.
I’ve only ever had 1 power outage in the last 5 years though and it was scheduled electrical work. couple of brownouts during storms that were just barely deep enough to kick in the UPS boost for a minute but nothing major. nothing else is critical enough to worry about it in my case.
but if I were in a place where power is patchy, I’d have enough solar+battery for the whole house to last a normal day/night cycle, then a UPS for the rack, then a generator as a last resort only.