You’re buying a home with security components
A new house may come with an existing security system. All the alarms and cameras work, are installed in the best spaces, and are ready to go. In this case, just pick up the phone to call and set up a new service contract. A Vivint professional will still come to your home to make sure there are no integration problems, and they might offer ideas on an upgrade or two. It's a quick visit, and you can get your alarm monitoring set up without paying for any new devices -- unless you get some new devices.
The previous owners can transfer an existing Vivint contract to your family for a small transfer cost to make the process simpler. If the owners downsize to an apartment complex or retirement community, turning over the security service might be a part of the sale.
You need to move and take your home security devices with you
You may want to bring along your existing Vivint system with you to your new house when you move. Luckily, it's pretty simple to accomplish, as many components are wireless. You can take down each device by yourself or use a Vivint expert to take care of your devices. Then an expert will set up the same features -- and any smart services you want to add -- in the new house. Your home security contract will keep the same.