If burglars can tell that someone is home, there's a greater chance that they won't attempt to break in. Remember, more break-ins occur during the day when many people are at work. For that reason, when you leave the house, create an illusion that someone's still there. You can leave a light on, along with music or your television for good measure. Of course, if you're going to be burning up that electricity by not turning off lights when you leave, make sure you've installed compact fluorescent bulbs that last longer and are better for the environment.
You can also mentally fake them out by putting a home security system sign in your yard. This won't guarantee they won't test out whether it's valid, but it could deter them. According to the Office of Community Oriented Police Service, most residential thieves stay away from houses with such signs [source: Sampson].