Attaching, Updating, and Binding External References

By attaching xrefs, you can

Coordinate your work with the work of others by referencing other drawings in your drawing to keep up with the changes being made by other users. You can also assemble a master drawing from component drawings that may undergo changes as a project develops.
Ensure that the most recent version of the referenced drawing is displayed. When you open or plot your drawing, AutoCAD LT automatically reloads each xref, so it reflects the latest state of the referenced drawing file.
Keep the names of layers, dimensioning styles, text styles, and other named elements in your drawing separate from those in referenced drawings.
Merge attached xrefs permanently with your drawing when the project is complete and ready to be archived.