My father-in-law once got a call from a security system rep.
They had a long conversation about his current system, which seemed to have ALL the features (would go off if any window moved, any person came near the house, always on, very little maintenance, could programmatically learn which people were welcome / not welcome, etc).
Try as he might, the salesman couldn't find a single way in which this current system was deficient, and finally he exasperatedly asked how much the system cost (thinking it must be very $$$, top-of-the-line).
"About $50/month in food + occasional vet fees. And he's one of my best friends too."