It's important to note that work units represent individual files within the Wwise project folder. These files are readable via a text editor and contain the information, properties, and relationships specified within the tool. Hierarchies of nested work units can be created in Wwise and organized in physical folders and subfolders. If work units are present in a subfolder for a specific category (such as the Actor-Mixer Hierarchy), they will be loaded with the project. This results in a finer granularity of files available for source control which simplifies development in a multi-user environment.
When working with a large audio team, it is often necessary to create enough work units to allow for a single person to work exclusively with a given work unit for a duration of time. If you are using the integrated Wwise Source Control solution, it is important to make sure you create a hierarchy that will work well with the file permissions established by the programmer.