You’re relocating to a place with home security devices
A new home may come with an existing 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 set up a new service contract. A Vivint installer will still show up to ensure there are no usability problems, and they might offer options on where you should replace bad outdated components. It's a quick visit, and you can get your monitoring set up without worrying about any new alarms and cameras -- unless you make additions.
The old owners can move an existing Vivint contract to your family for a small set-up cost to make your life simpler. If the outgoing residents downsize to an apartment or retirement community, turning over the Vivint contract might be a part of the sale.
You want to move and bring your home security components with you
You may need to take your old Vivint system with you to your new place when you move. Luckily, it's fairly easy to accomplish, as modern alarms and smart devices are plug and play. You can uninstall each device by yourself or call a professional expert to take care of everything. Then an expert will put in the same components -- and any smart items you need to add -- in your new place. Your home security contract will keep the same.