I still believe that this is 90% of "preppers". They study it for a week, make some arrangements an then just let it go. Revisit those arrangements once a year or so and you are golden.
Generally you aim at basics.
* About 3 weeks worth of food (2000 kcal/person/day)
* Week of water (gallon/person/day), some basic water filtration (Sawyer squeeze)
* Some preps may be more in line with local climate (backup heating for cold environments)
* Evacuation bags are very common and are also known as BOBs (but most are garbage with lots of guns and no water). Still good to make some with copies of important documents, some water and spare clothes. Just get your old spare bag and unused clothes, no need to overthink it.
* Think about having more first aid material and skills
* Hygiene can be pain once your toilet does not flush anymore and you can't wash your hands, make some arrangements for that too (ie. bucket and plastic bags are way better than nothing)
* I'd also consider tools, such as headlamp per person, other depends on location and needs. Axe can be useful even in city in case of earthquake. Fixed blade knife is probably most versatile tool and Morakniv companion for 15 USD is usually sufficient. But I would suggest some practice here too, you don't want to get cut during temporary service disruption.
Good luck. As German governmental pamphlet states "Germany is ready, when every German is ready". Replace with your own country :).