Preference Settings

What should the settings be in order to share iTunes media files? All files are saved in the Public folders. I set up files for audiobooks in my wife's account. When I open iTunes from my account, all the changes made from my wife's account are undone. The files cannot be found and I must go through the process of locating missing files. I could go through a multitude of issues (updating library when songs are added by another user, why does warn me only stay selected on my wife's account, etc.). However, I would like to know the advantages of Home Sharing and Authorizing a Computer.