We’ve been very fortunate in our area in that power outages are few and far between. One datapoint: we’ve been in our home for about 9½ years, have experienced four outages. One lasted 36 hours, and the other three were less than four hours each. Our previous home in central Ohio had short outages frequently and one that lasted a week. After that long outage, we installed a 20kw natural-gas-driven generator which pretty much guaranteed we’d never have another outage. And we didn’t. The unadvertised downside of whole house generators is that they consume huge amounts of expensive natural gas or even more expensive propane if you’re using them for long periods of time such as 12 hours or more. And for really long, multiple day outages you may need to shut them down at times because of noise for your neighbors (a neighborhood without power is very, very quiet and any noise is very noticeable and carries), or to perform some service like an oil check or oil change.