It is not like this here, we have blackout caused by failure in electric network, mostly caused by overload or storm, but they usually fix it in 15 minutes to half an hour, sometimes 2-3 hours, once in two months or something. But I want to underline again, depending in which area you live in, blackouts are more or less common. In areas with a lot of illegal building obviously electric network is not in perfect condition, but in urban developed areas it is better, and blackouts are not so often. Anyway for all this problems UPS is enough.
Those are my experiences.