BlueBrick can manage a limit number for each part in the Part Library. This set of maximum/limit numbers is called a Budget. The main goal of the Budget is to easily check if you will be able to build a layout designed with BlueBrick with your actual LEGO® collection. If you decide to use a Budget, BlueBrick can simply warn you if your layout contains more parts of a certain type than what you actually have in your collection. It can even prevent you to exceed that limit when you design your layout.
For each part in the library, you can define a Budget Number (read the Using a Budget section for more details) and save the whole collection to a file. By using several files you can of course manage different collections, for example one file for your personnal collection and one file for the merged collection of your LUG/LTC used for collaborative projects. Read the Saving and Loading a Budget section to learn more about how to manage budget files.