I have found that home owners with young children can be great repeat customers. You can clean for them every 6 months until their kids graduate from high school.
Older folks can be good and have extra cash but, they don't think they need cleaning as often. (They blame the need for cleaning on their grandchildren) Many will never clean their carpets until they move to the retirement home.
Every age group may need a different type of advertisement.
Example off the top of my head-
Young- Removing spots kool-aid, remember how the carpet used to look?
Older-Cleaning saves money on replacement, With your special the more you clean the more they save!
Oldest- Cleaning for heath, Carpet protector to protect from grand children.