Documenting UI hierarchy for games

While working in games I realize how important is documenting UI design in a daily basis. There is so many iterations, testing that some how you loose track of what you changed and why you changed it. Documenting UI and UX rules for our games make us look back easier on why we took that decisions, so next time we can make it better, also if the team changes there will be guides for the next to jump in the project and see what is going on.