Your new place has an existing security system
Many times after you buy a new house, you’ll find that the old owners left a smart home system. All the alarms and cameras work, are installed in the best places, and are ready to go. In this instance, all you might have to do is to call and establish a new service contract. A Vivint installer will still come out to ensure there are no compatibility problems, and they might offer options on an upgrade or two. It's a preliminary appointment, and you can have your monitoring set up without worrying about any new devices -- unless you add on.
The old homeowners can give an existing Vivint contract to you for a nominal transfer cost to make the process easier. If the outgoing residents are downsizing to an apartment complex or retirement community, turning over the Vivint contract might be a condition of the sale.
You are looking to move and take your home security equipment with you
You may want to take your existing home security components with you to your new house when you move. It should be fairly easy to transfer, as modern alarms and smart devices are wireless. You can take down each alarm or camera by yourself or use a professional installer to take down the system. Then a pro will set up the same devices -- and any new items you want -- in the new house. Your home security contract will remain the same.