Getting a new residential customer who actually appreciates your work and pays promptly for that work should be cherished. And, I deliberately use the word cherished. You worked hard and sometimes paid a great deal for that new customer.
You never want to willingly lose a customer. So, from the very beginning, everything must be done properly to retain the relationship. Sometimes, continuing that relationship means maintaining communications while the customer moves from one location to another and then to another location. As long as the customer is in your territory, you want that customer. And, if the customer leaves for another city, then returns, you want that customer back. And, don't forget the potential new customers from the existing address.