now that I'm on the other side of a day of work, I have an addition to this, which I am surprised no one mentioned! When I think about a post apocalyptic scenario where the electric grid is down, and internet doesn't work, I always fixate on two things: food and fixing things. To fix things you need tools! I think a good set of tools, kept reasonably maintained, can last lifetimes. (especially the static tools like combination wrenches, drivers, hammers. Ratcheting wrenches are great too, but less likely to last a lifetime if used much, so I suggest having a few backups ;)