I’m writing a fantasy story set in a desert. This has presented a number of problems; what do you build your houses out of when you have very little wood, where do you get water, what do you eat? I have spent a very long time working out the answers to these and many other questions. So how much of that does the reader need to know?
Obviously the first thing to consider is the length of the work. If it is a short story you probably don’t need to go into detail about the politics of the day and how the city is physically able to run if those things are not pertinent to the story. On the other hand, if you are writing a novel then you may want to sprinkle at least passing references to those things.
The story I’m writing is a novella, so I don’t want to over-burden the reader with proof that I’ve thought about how the world could work, but I also don’t want to bug the reader with them thinking what I’ve got happening isn’t possible in a desert. It is a fine balance to strike, and I’m pretty sure that what is enough for one reader will not be enough for another.
Perhaps in future, along with the map and the cast of characters that some fantasy novels are adding these days, you can have an appendix of how the world works? You could attach all your notes about the reed species used in the water filtration, the method of creating durable building materials and the political set up. Then again, maybe that stuff is best left in the bottom drawer?