Determine if the ending s in the family last name holds the "s" sound or the "z" sound.
Add an -es to pluralize surnames that end in s with the "s" sound. "The Brasses are coming over (not the Brass's). "The Joneses are at the game (not the Jones').
Add no ending to surnames ending in the "z" sound. These names need no "s" at the end or apostrophes. "The Lodges are coming over" (not the Lodgeses). "The Stevens are at the game" (not the Stevenses).