Frisket is correct. Most burglers know all the tricks of the trade. Like you and me, they get a lot of info from the net. They learn what windows, doors, locks, alarms etc are the easiest to access and bypass.

As for a having a dog and it's inherent expenses, there was a news show on TV a few years ago where former burglers detailed that the average family dog and most "trained" dogs are easy to distract. Some of the burglers favorite tools/toys they carried and used against dogs were everyday things such as tennis balls, chew bones, dog treats etc.

One of the burglers also stated (I'm paraphrasing here) "If the home or building contains something we really want, no dog is a deterrent and we will take any means to remove the dog from the equation."