I don't like it when I go back to a tab and it reloads.
For whatever reason, I want tabs to stop changing.
I don't want the to reload from their javascript
and I don't want the tab content to be deleted by the automatic discard (to save memory)
If firefox decides to free memory, it should dump tab data and tab state to disk, not delete and reload from the website later.
Sometimes the website won't exist later.
Somewhat related but this one is hard : Some website dynamically delete content after you've scroll past it (firefox) this means even if you scroll to the "true" bottom, you can't ctrl+f search and you can't freeze the page and read it all at your leisure and preserve it for later.
Currently my solution is to video screen capture the whole tab while scrolling slowly, this is quite a ridiculous step to take but apparently the only option to keep our data !?
Hmm, I'm not sure.
I think you can set up automatic saving of tabs, but that is probably not what you are looking for, but also it will be in the way while the process is ongoing for the current tab.
Other than that, I think I have read that it can be controlled from other addons, like starting a new save, so maybe you could make a simple addon that can decide when to trigger saving a tab, then unload the tab and replace it's URL with the result of the singlefile save.