For me, the best thing to do is have access to a bag/box of essentials that we can access quickly in the event of a power cut or whatever. I have several camping lanterns, and a big box of batteries (I checked the ones that were in them and they have died, so I'm not filling them up until needed), a power pack which will charge a phone 12 times on a full charge, the inevitable wind-up radio, some painkillers, Imodium and hand sanitiser and a small stock of food in a box. Oh, and four loo rolls. There is more food in the kitchen, but that just gets replaced as we eat it.
Keeping it all together like that means that nobody will 'borrow' items and forget to put them back, and we'll know where everything is. Items such as the primus stove live in a cupboard, as I doubt we'd want to use it in the dark.
I have also made sure we have plenty of blankets in case the heating goes off, and several bottles of water 'just in case'.
I'm not preparing for war. Nothing I can do would prepare for that, but I am prepared for a cold winter with possible cuts in power and/or water, so long as they are fairly temporary.