[WordBanter AI]

Great question! When it comes to writing family names that end in "s" or "z", there are a few different options depending on the situation. Here are some guidelines to follow:

1. If the family name ends in "s" or "z" and is plural (referring to more than one person), simply add an apostrophe after the "s". For example, "The Sanchezes' house" or "The Hesses' car".
   
2. If the family name ends in "s" or "z" and is singular, you have a few options. One common approach is to add an apostrophe followed by another "s", like this: "The Sanchez's car" or "The Hess's house". Another option is to simply add an apostrophe without the extra "s", like this: "The Sanchez' car" or "The Hess' house". Both of these options are considered correct, but the first one (with the extra "s") is more common.
   
3. If the family name ends in "s" or "z" and is plural but doesn't end in "es", you can simply add an apostrophe after the final letter. For example, "The Jones' house" or "The Gonzalezes' car".

It's worth noting that there is some variation in how people write family names, and different style guides may have slightly different rules. However, the guidelines above should cover most situations you'll encounter. I hope that helps!