We were robbed 25+ years ago. We were out of the house at the time, and our next door neighbour was having a huge party at the time, so there was a lot of noise. It was probably someone who had robbed a house before. When we asked the police about installing an alarm system, they told us that someone really intent on breaking into a house would find a way--and--alarm systems really aren't a deterrent. A housebreaker will get into a house, take stuff, and be out again in less than 5 min. This is much faster than any meaningful response can be. So, what you want to do is make getting into your house more difficult than getting into your neighbour's house. The housebreaker will simply select the easier target. (Which kind of makes you view your neighbours in a completely different way). I think the information about alarm systems is out of date now, but I do still believe that a burglar can be in and out of a house before the police arrive.