Since Bunkerchan lacks a system like Desuarchive for saving content that falls off the boards, any threads posters may have interest in should be saved at archive.is and web.archive.org (Wayback Machine) if they don't want to lose their content for future reference.
Archiving content lets older posts/threads be found faster (especially if you repost the archive link in another relevant thread).
This subsequently offsets pointless rehashing and other wasteful issues in threads. It also means that images that were once posted here are still saved for you even if they have been deleted in other places on the internet or if your hard-drive goes FUBAR.
When using Wayback Machine/Archive.is to archive pages, remember that any images you wish to archive in full resolution must have their html archived separately. In other words, you have to open the image in another tab, copy the link and save it in the archive(s). This is especially important with spoilered images, since they won't be even visible in an archived page unless saved individually. This may be a lot of work but if you want those images you'll do it, even casually saving 1 image a day per thread will already be helpful. Both Archive.is and Wayback Machine have optional free browser extensions for easier use.