One other thing. Many alarms will SEIZE the phone line to phone the alarm company. That is something to consider. If you have a cell phone no problem. If you are wanting to call the alarm company and cancel you have to wait until the alarm releases the phone line.
But you don’t want the alarm to relinquish the line before calling the cops. In a home invasion situation, you do not want the bad guys to be able to in any way prevent that outbound automated call or inbound human call from the alarm company. You want the alarm system to seize the line and call out. Call the alarm company with your cell phone to cancel the alarm, if necessary.
Of course, the limiting factor on the protection the system gives is the response time of the local cops. If they are told an alarm has been triggered at a residence, they don’t usually lay rubber getting there. You need a dog and a bunch of guns.
In addition, you need to think about and rehearse how you will deal with cops when they do show up so that everyone involved is safe. The cops will probably ask you to leave the house and walk away from it with them so they can make sure you’re not being constrained.