I haven't explored enough caves in the game to figure this out yet:
When you re-enter a cave does it re-spawn? For instance, are the layout/mobs/items completely different when you re-enter?
If my memory serves, it goes back to the purple (? — I'm color-blind–) world screen whenever you re-enter. But, I've been unable to figure out if the map is any different. This is mostly due to my lack of ability to survive long enough to find out. 🙂
Best Answer
In the current version (All's well that's Maxwell), caves do not respawn/regenerate anymore.
In earlier versions/builds/releases of Don't Starve, caves were a work in progress. When you entered a sinkhole, you got a dialog telling you this, and asking if you wanted to enter, stay above ground or regenerate the cave.
A lot of guides or wiki pages still reflect the possibility to regenerate caves and harvest all the resources again. For some resources (gold, stone, gems, flint, ...) the "earthquakes" actually do supply infite resources (albeit at a slow pace), other resources (mushroom trees) are in fact finite and should be gathered carefully.