The number one way to avoid having your house robbed is to live in a shack guarded by a one eyed dog. If you wish to take this route, make sure the outside of the house looks like the underside of a dock, and the windows are crumbling back into sand. The yard must look like an open-pit graveyard with plant life irritable enough to strangle any stray cats. There must also be piles of rusty spikes that look like skeletons in the grass.
Now, do not be discouraged by the difficulties that may arise in creating a house this way...neighbors coming to complain and falling in the traps, mail men getting eaten by your dog...because the inside will be well worth it. It, of course, can be as rich and comforting as you can afford.
Now, in the event that you are simply not keen enough to take this route, then you must realize that your house WILL be a target. And that means that you must have a defense system.
To avoid getting into a history lecture on the medieval war strategies of fortresses, I will be brief in describing a few possibilities.
In the case that your property agreements do not permit the construction of a moat of lava, walls or fences are the next best things. In the case of walls, spikes are ideal for the tops. And for fences, a few hundred amps will keep away any falling leaves, let alone any ambitious, cocky thieves.
If, in the unlikely incident, someone was to get within the walls or fences, the yard must have a series of traps. Bear traps are effective, but not so subtle. Therefore, I would suggest poisonous darts attached to an infrared sensor. These contraptions are relatively easy to create. The dart need only compress a spring into a cylinder with a trigger to keep it in. The infrared sensor can be bought at your local hardware store, reconstructed to aim with a few servomotors controlled by a simple chip, and voila, you can aim and fire from the comfort of your living room.
In the case that you are not as well trained in the art of the mad scientist, you may always take the barbaric alternative. In this case, the yard must be guarded by a monster. Monsters are not as difficult to find as you may think. They normally reside in dark, drippy places like caves, sewer systems, and deep trenches. Some popular monsters include three-headed dogs, dragons, and swamp monsters. If you would like more information, please refer to the chapter, “How to hunt, trap, and tame Monsters”.
Moving right along. In the unlikely event that a thief or extremely (un)lucky kitten happens to make it alive to your door or window, there are a few things you must know. Firstly, locks are clumsy and easily broken. At the same time, there must be a method for the door to identify you, and to not treat you like a victim, I mean, thief. And that is the use of your key. It must look ridiculous, like scrap metal or a mangled fork with eight prongs. The idea, simply, is that no one will think it has any meaning or value. This key however, is very crucial. It will not unlock anything. Instead, it will turn off the Weapon.
The Weapon is something that will be sure to stop any thieves dead in their tracks. It varies in size, usage, and strength, and is a very versatile and creative invention. In fact, it can be as creative as you wish. Some popular Weapons include lasers, machine gun turrets, flame throwers, trap doors to alligator pits, and the famous instant-freeze that will start your statue collection with a bang.
Now, if you are away from your house for long periods of time, make sure that there is a room in your house that contains millions of shiny pieces of plastic and a falling jail cell door. This is just for those rare incidents when somebody parachutes down to your top floor window with a suit of armor and a go-go-gadget tool kit.
Other than that, you are set.