It appears users are removed from the passwd file when they no longer need access to a server at my current organization. I am finding files with a UID but no associated login. At a previous organization I worked for - they would lock the account, thereby preserving the login.  What ways have other organizations addressed old logins?  Do you move ownership to another user or change permissions so that anyone in the group modify the file?  I am just curious what are good ways to handle old logins.  I am not the administrator but it is frustrating to not know who owns a file or be able to make changes.  Some of the files are extremely large and seems wasteful to make a copy.  I think the administrator would be open to suggestions if I made a pitch for a new method.
Rules for File Ownership when user is leaving company
files;ownership