You’re moving into a house with security components
A new home may come with an installed security system. All the devices function well, are placed in the correct spaces, and are ready to go. In this case, just get 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 problems, and they might offer suggestions on upgrades. It's a preliminary trip, and you can get your 24/7 monitoring set up without having a bill for any new devices -- unless you get some new devices.
The outgoing homeowners can give an existing Vivint contract to your family for a one-time set-up fee to make your life easier. If the outgoing residents are downsizing to an apartment or smaller home, turning over the security contract might be a condition of the sale.
You want to move and bring your home security equipment with you
You may need to bring along your old smart devices with you to your new home when you move. It should be fairly easy to accomplish, as modern smart devices are plug and play. You can remove each alarm or camera yourself or contact a Vivint expert to come and take care of your devices. Then an expert will put in the same features -- and any smart devices you need to add -- in your new home. Your home security contract will remain the same.