(If you are reading this without context, either via link or in the "Recent pastes" section, click on my account and read my previous paste)
 
I'm using electronics as the example in this post, but it applies to other things.
 
Many people will ask me, "Why do you need to build electronics in a post apocalyptic scenario" or other similar questions. The answer is; you don't. But it will help a lot. Once you have your crucial supply chains set up, electronics can make further gathering much easier.
To provide some examples: Radio for keeping communication with field teams.
Lightning.
Farm equipment (Not necessarily electronic, but related).
GPS (assuming existing GPS systems are still functioning, although there are ways around this. I will explain further down)
 
And, one few people ever consider, Luxury: So many survivalists underestimate or entirely dismiss the importance of luxury. A caveman who has never had any concept of luxury will probably not care, but it would be all but impossible for modern humans to transition from a society with internet, TV, radio, cold food, etc. to a bare minimum society with almost nothing. I always say society is too pampered, but this this only to a point. Sometimes no crucial work needs to be done, and would infact be wasteful. If people have nothing to occupy themselves with, mob insanity slowly sets in. This could be anything from the consumption of harmless drugs (marijuana, mushrooms, etc.), to the creation and consumption of simple games, electronic or otherwise.
I'm not saying these things should be a priority, and during the initial stages of creating a long-term settlement there will always be work for people to do. But once it is stable and self sufficient, that is not the case. At this point the implementation of both luxuries, and simple tools to make our lives easier can begin.
 
If you are asking yourself "Why not learn the skills after the fact," you're an idiot. If you don't have even a basic understanding of how electricity is generated, it will take decades if not longer to figure it out again. Agriculture is a relatively recent invention. The promise of, and eventual implementation of the technologies of the previous society are the only thing that will prevent people from giving up. Would you rather live in a society where you constantly had to do difficult, wasteful tasks to even survive, or one where you could do things you personally enjoyed in your spare time without fear of starvation and death?
 
On the GPS thing: GPS satellites should theoretically function for approximately 200 years before total failure, but small orbital corrections are necessary to maintain accuracy. If and when using their signal is no longer practical, the use of ground stations in place of them would work fine, but you'd need to be within range of them.