I have a multi-level system of protection in/on my house.

 

The most basic is a dog.  I'm down to only one now, but their hearing and ability to wake you if you're sleeping works really well without question.  Even if my dog is asleep she will hear the front or back door open (I don't have a real big home).

 

I have a pretty good alarm system on my property which includes cameras.

 

The final line of defense is a few choice weapons hidden in strategic areas of my home.  My wife and I are both trained on how to use said weapons including the important issue of knowing what you're shooting at and what is behind your target.

 

After those lines of defense I have a cell phone where I can call 911.

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