Access, by using references and VBA, enables developers to create their own libraries of VBA modules. As with add-ins, each library can then be used in multiple or distributed applications. There are a number of pros and cons to using code libraries.
Here are some of the pros of using code libraries:
Code libraries enable you to create routines once and then use them in multiple applications. This reduces redundant code.
When changes are made to the code for fixes or additions, they have to be made in only one place.
If you want to distribute your library to clients without letting them have the source, you can make an MDE from the library, but still give them the source ...