[Kosmos]

Because of the way UI Builder treats us, and knowing full well I will fubar the mod I"m working on at any moment, and may not know how to fix it.
I keep many, many revisions of a window I'm working on.

Everytime I save in UI Builder, and before I go into the game.

I do a copy/paste of the files, in the my modding default folder.

this saves a file Copy(1)_of_eq2_mainhud_tracking.xml

or whatever. then I also paste it into my custom folder for the game which overwrites the last version I tested.
It's common for me to have as many as 15 copys of the file. Each significant change I make gets this treatment.

When I'm done and happy with everthing. I'll archive them for a while, and if I don't run into any issues I'll delete them.

You can NEVER have too many copies of a file as long as you keep track or your progress. the easiest way I've found to do this is the copy/paste in teh same directory, because it will just put the 'copy of' part on there for you, and add to the count each time.