You’re buying a place with home security devices
A new home may come with an installed home security system. All the components work, are hung in the right spaces, and are ready to go. In this example, just get the phone to call and establish a new service contract. A Vivint professional will still show up to ensure there are no compatibility issues, and they may offer ideas on an upgrade or two. It's a fast visit, and you can get your monitoring set up without worrying about any new devices -- unless you add on.
The previous owners can move an existing Vivint contract to you for a small transfer cost to make your life easier. If the previous owners downsize to an apartment or smaller home, turning over the Vivint contract may be a condition of the sale.
You are looking to move and bring your old components with you
You may need to take your existing home security components with you to a new home when you move. That’s pretty easy to do, as modern components are wireless. You can uninstall each alarm or camera yourself or contact a professional installer to come and take down everything. Then an expert will hang the same components -- and any smart items you want to add -- in the new place. And your home security contract will keep the same.