Excellent watchdog without being excessive

My Schnauzer alerts me to anything unusual at the perimeter with two sharp barks and then waits for my response. If I go to investigate and find it benign he stops. He does not bark endlessly like some small dogs. He has a purpose to his alerting that seems intelligent and measured. He has deterred one attempted break-in and alerted me to a pipe leak. His watchdog instincts are genuinely useful.