vrkelley brings up a good point: lock up your bike even at home. I live in a very suburban area and the police will be the first to say that the most common way bikes in our area are stolen is right out of people's garages! It's that "opportune thief" who sees an unlocked bike in a garage and makes off with it. It's not unusual for me to be out walking the dog and see an open garage with no one around so I'll ring the doorbell and let the occupants know their garage door is wide open. They're always grateful.