The sound of breaking glass doesn't provide much of a deterrent to burglars, but if your window security is lax, they can come and go without ever making a sound. Criminals often find a way into your home prior to breaking in—as part of a cleaning or repair crew, say—and simply unlock a back window for easy access later. So, routinely check windows to make sure they’re latched. Easy-to-access basement windows can be barred with a metal grate. Remember, too, that curtains or shades keep big-ticket items hidden; if a crook can’t see your goodies, he’s likely to try a house that has them on display.