I have also brought a second portable sized UPS for my modem now as well meaning if I get a powercut my VDSL and most of my network should stay online now.
Has my UPS ever kicked in? yes even in a city it has probably easily kicked in dozens of times. In about 5 years have had maybe around 10 full on power cuts (most less than 10 minutes), and probably at least 3 to 4 dozen brownouts.
Also there is correction applied to the voltage if its out of spec by decent UPS.
Edited by Chrysalis (Fri 09-Apr-21 08:57:44)