Is your home actually safer from burglars if you leave your lights on? That's a question NPR asked and tackled in a recent article.
And the answer seems to be that there's no easy answer. The NPR piece points out that on the one hand, if you leave your lights on, burglars will think someone is home and may not choose to break into your house. On the other, if you turn your lights off while you're away, burglars won't be able to see once they're inside. Plus, if you keep your lights on all the time, you might draw unwanted attention to your apartment from others who may catch on that you're simply doing it as a trick.
One Neighborhood Watch trainer for Washington, D.C.'s Metropolitan Police Department recommends to NPR that people install timers to mimic regular activity. Harry J. Houck, President of Houck Consulting, Inc and a retired NYPD detective, tells Brick Underground that leaving lights on all day and/or using timers aren't bad ideas, but most burglars today know all these tricks. "The truth is that most burglaries happen during the daytime, and most burglars will knock on a door or ring a doorbell before breaking in to make sure no one's home, regardless of whether or not lights are on."
The reason, Houck says, is because a burglary turns into a violent crime if a person is present, and most robbers try to avoid that, both in New York City and more suburban spots. NPR points out that neighbors can be helpful in preventing burglaries, an idea that Houck agrees with, especially in New York City, where we all live on top of one another and can really keep eyes and ears out for each other.
Houck says it helps to alert neighbors you trust that you're going on vacation so if they see something fishy, they call the police. But he also recommends stopping the newspaper drop-off and other deliveries when you're going away for a while, so nothing piles up outside your front door (which can be particularly important if your stoop is visible to the public, in other words, if you live in a brownstone, but will also help keep your whereabouts secret to building staff and neighbors you may not know as well in larger buildings).
And, especially in buildings without doormen, "make sure your windows are locked when you go away. Most burglars will enter through an open window. Breaking a window makes noise and they know neighbors will hear that."