Houses are the core of your town in CashTowns and should not be taken as anything else as the top priority. And with the new changes the admins have added it's more important then ever. Read about the new rules
here. So here is some information that you need for developing your houses in your town.
Houses are the only buildings that can be upgraded to level 10. Without empty space in at least one house, you cant recruit new citizens. Every citizen needs a house to live in. The houses accommodate up to 20 citizens at a time, depending on the level. If you want to find the house capacity multiply the level with 2.