Do you have an alarm system in the house really protect?

I wonder if anyone really has been protected by a home security system. I mean, was not an intruder, fire, or something that happened and the alarm for help. Any personal stories and other sources are seen

I have an alarm system and I I'm glad. It has protected me on several occasions. First, I have the medical alert button with my system that calls an ambulance when one is needed. I fell down once downstairs and opened the head bad enough to require stitches and a visit to the emergency room. Secondly, my alarm went off indicating a violation in the back door of my house. Police arrived and saw very large boot prints in the mud leading to it. That same night a house in the neighborhood was invaded and I can not help but wonder if the intruder tried my first home but was scared by the alarm blarring.

Undue Alarm – Source Recorder Video