You moved into a home with a pre-installed security system
Sometimes when you buy a house, a home security system is already in use. All the alarms and cameras work, are hung in the right places, and are ready to go. In this example, you might discover that you have to call and establish a new contract. A Vivint installer will still come out to ensure there are no integration issues, and they may offer ideas on where you should replace bad outdated components. It's a fast visit, and you can get your alarm monitoring set up without worrying about any new components -- unless you get some new devices.
The old owners can transfer an existing Vivint contract to you for a one-time set-up cost to make your life simpler. If the previous owners are moving to an apartment complex or smaller home, turning over the security service may be a condition of the sale.
You need to move and take your home security components with you
You may need to bring your old home security components with you to a new home when you move. Luckily, it's fairly easy to accomplish, as most smart devices are plug and play. You can remove each component by yourself or contact a Vivint installer to take down the system. Then a pro will put in the same features -- and any additions you need to have -- in your new home. Your home security contract will stay the same.