The area where I lived had moderate vehicle traffic and almost zero foot traffic. Thus, if I saw someone walking up to my house, they are already suspect (I know who my neighbors are); especially since I have "No solicitors" and "No Trespassing" signs posted on my fence....my first line of defense
Second line of defense is the 75lbs Lab
Third line of defense are the front and back doors.
I am the last line of defense. Three strikes...and they are out.