You're about to go to bed. You flip off the light switch. It's pitch dark. As you stumble your way through the living room, you glance at your neighbor's house where light is peeking through the windows.
You stop in your tracks and wonder: Would a burglar choose to break into your dark house or your neighbor's brightly lit house?
Scouring through online forums will give you two contradictory answers: Leave your lights on, and burglars will think someone is home; turn your lights off, then burglars won't be able to see what they're doing.