Dogs can buy you that early warning....
I was starting to think no one kept "house" dogs anymore. Dogs are one of the best deterrents and proactive alarm systems going.
Ours usually go off before the drive and perimeter yard alarms do, and everyone knows it too, including anyone outside. If somehow, someone were to make it inside the house, 250 pounds of PO'd Rottweiler will let you know just where the problem is. No need to clear the house, and you'll now exactly who is who if family are moving around.
You dont even have to be "in" the house. In the yard, the bodyguard is always right there with the rest of the family.