After you are done with an object, you should release it so the memory that it is using can be freed.
As long as a VLA-object points to a drawing object, AutoCAD will keep all the memory needed for the object. Different variables can point to the same AutoCAD entity in memory, you can have multiple VLA-objects pointing to the same drawing object. You can compare two VLA-objects with the equal function, which returns T if both objects point to the same drawing object.
After releasing an object, it is no longer accessible through the VLA-object pointer. This is similar to closing a file. No memory is necessarily freed when you issue vlax-release-object, but AutoCAD can reclaim the memory if needed, once all references to the object have been released.