Why Rename a File

Context:
In our class we normally give two reasons we should change file names (we are talking mainly about files made using Microsoft Office Word or Excel):
1) To make it clearer what a file contains (like not Letter.doc, but LetSuplMar2004.doc)m
2) Making it possible to sort them better (like ListDept001.doc, ListDept002.doc, etc).

Question?
Are there other good reasons for renaming that we should mention teaching beginners?

Thank everyone in advance.