Ok so I wanted to do a clean install of skyrim and CK without all the mods/textures etc Id been playing with, so uninstalled both and reinstalled. but when I copied the mod I was making all its scripts were gone, as in I could no longer access them in CK. Now I knew scripts were stored seperatly and it was stupid of me not to back them up but it got me thinking. Which files do we upload to workshop/nexus and which files do we backup when we want to continue working on a mod? can anyone break it down for me?

We want to keep the esp or esm file.
If the mod uses any custom textures, meshes, sound files, lod files etc, you must back them up. (if you use your own BSAs, then it works backing that up as well)
Scripts too!

I was told that feature was broken, does it work?

Which feature do you mean?

Clicking on file, then "Create Archive"

I don't know, I've never used that..
I do manual backups of my important files.