Take a Peep!

Of all the security measures you can take, few require as little labor as putting a peephole into exterior doors. Go for a 180-degree-visibility type to give you a full view of anyone knocking on the door. In fact, splurge a little and buy the larger-sized model; you'll squint less and a one-way mirror blocks anyone from peeping in on you. Plus, it's a simple installation process: Just drill a hole at a height everyone can see through, then screw the two halves of the peephole together.