Consider the happy, working, married couple sharing one last name. Mail comes to them as well as to him or her. She doesn't know, either. Mistakes get made. Requested items get junked.
Somebody gets mad.
But life in a modern marriage is busy, especially when there are kids around. Mail piles up on counters and tables. By the end of the week, the happy home looks like a place social workers take kids from. What a mess, and all over the mail. Both have successful careers in academic fields that require organization.