St. George has about 38,600 households, according to the Census Bureau's 2024 estimates, and the towns around it keep growing too. New subdivisions fill in every year. People who just moved in haven't picked their plumber, dentist, landscaper, or favorite lunch spot yet. A postcard that shows up in their first few months has an unusually good shot.
The flip side: at this size, mailing the whole city at once gets expensive fast. The work is in picking the right slice of it.