Leave your bathroom lights on.
“If you want to keep burglars out of your house, leave a bathroom light on all night. The bathroom is one place where somebody could be, for any length of time, at any time of the night and we would be likely to hear the slightest strange sound. Burglars know this and won't try to enter. It's also the cheapest possible protection. The kilowatts are a lot cheaper than your valuables.” - From Malcolm X’s stealing days