My partner and I live aboard a sailboat outside of reliable internet range for most of the year, we keep copies of safety guides such as Field Manuals(FM Series

My partner and I live aboard a sailboat outside of reliable internet range for most of the year, we keep copies of safety guides such as Field Manuals(FM Series), barefoot doctor, plant identification guides and other repair manuals for the boat. We also have copies of all our projects, and the documentation for the languages they use. We have redundancy in our devices, so secondary laptops and SBCs to replace them with would they fail, as well as SD cards with imaged distros to bring them back up if we brick them. We're not especially fans of kiwix and these wikipedia archives, they're hard to duplicate being so large, too slow to access from SBCs and the content too superficial to be of any use. Instead, whenever we have internet access we hand pick the websites we'll need and make mirrors. We don't keep anything crucial on electronics, we make printed copies of the important things, we have physical copies of entire courses on trigonometry and celestial navigation. We tend to rip websites into plain text format, and format it when needed, sometimes we rather not have to fire up the browser just to look at the size of part we might need to make, instead we just cat the file.