You’re buying a place with home security devices
A new house may come with an existing home security system. All the alarms and cameras work, are hung in the best places, and are ready to go. In this instance, just pick up the phone to call and start a new monitoring contract. A Vivint expert will still come to your home to ensure there are no compatibility issues, and they might offer options on an upgrade or two. It's a quick visit, and you can have your 24/7 monitoring set up without worrying about any new components -- unless you make additions.
The old homeowners can transfer an existing Vivint contract to you for a nominal transfer fee to make the transfer easier. If the previous owners downsize to an apartment complex or retirement community, turning over the home security contract might be a part of the sale.
You need to move and bring your old components with you
You may want to bring along your existing Vivint system with you to a new place when you move. It should be pretty easy to do, as most alarms and smart devices are portable. You can uninstall each device yourself or use a professional expert to come and dismantle your devices. Then a pro will put in the same components -- and any smart services you need to add -- in your new place. And your home security contract will remain the same.