You know not to leave a key under the front mat, but do you know which appliance should be set to a timer while you're away (hint: it's not the lights)? Home security experts share the five best things you can do to protect your nest while you're away.

After a long weekend relaxing on a Caribbean beach or two weeks on that dream trip to Australia, you pull into the driveway and think, "Funny, I swore I closed that window." And that's when it hits you: You've been robbed. Most travelers worry about getting their wallets stolen or passports pinched while on the road. But you should also take steps to protect your home while you are away--especially since more than 2 million burglaries were reported in 2011 in the U.S., and that number goes up every year (almost 2 percent since 2002). And in 2011, victims lost $4.8 billion worth of property. Odds are you will come home to a house that is just as you left it, but these five tricks are so easy, it's not worth taking chances.

Burglarize yourself

No, you don't have to sneak up to your front door wearing a ski mask. Security expert Chris McGoey suggests taking a critical look at your home and finding any security lapses. He even organizes block parties where neighbors help neighbors make their homes impenetrable. Once you find your way inside, think like a burglar. Look for quick things to grab (like the iPad on the counter or the checkbook on the desk). And if you are leaving a car in the garage, don't hang the keys on the hook by the door. "They can just load up your own car and drive away," cautions McGoey. He also suggests rethinking your hiding places, like that jewelry or cash in your sock drawer. Everyone does it, and burglars know that. Wondering if you missed anything? Consult your teenagers. According to McGoey, "Chances are they've already ransacked your house."

Keep it clean

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Every expert's top tip for keeping your house safe while you're away is to be neighborly. And that goes beyond waving across the driveway and buying Girl Scout cookies once a year. Keep a trusted neighbor in the loop about your vacation plans. While you are away, they can keep an eye out for flyers and papers accumulating on your front stoop that scream, "No one has been home for days." Other red flags for an empty house are a snow-covered driveway or a messy yard. Sweet-talk your neighbor into shoveling your driveway and front walk if there's a snowstorm while you are away, or trimming your grass if it starts to look unruly (but be prepared with a thank-you souvenir when you get back). Chances are they will go on vacation someday, and you can return the favor. Isn't that what neighbors are for?

Don't recycle

Putting out the recycling before you hit the road is just one more thing to check off the pre-vacation to-do list. Consider this, though: Those boxes from your new TV, computer, or tablet aren't trash as much as advertisements for the great new gadgets just inside your door, warns Kern Swoboda of the New York State Police. Whether you are traveling over the holidays or not, it's best to wait until you get home to put out the recycling. If you can't stand the thought of coming home to clutter, another option is to bring everything straight to a recycling center. Putting out the trash too early can also be a beacon for burglars, as are empty trash cans sitting on the curb. Yet another thing that friendly neighbor could help with (make that a really nice souvenir).

Make your house look inviting

The knee-jerk reaction when going away is to close up your house like a tomb. Of course you should lock all the doors and windows. It's the blinds and curtains you should leave open. It may seem like a good idea to keep anyone from seeing inside your house, but Swoboda actually recommends leaving the blinds open if you usually leave them open. Burglars notice details like these.

Don't just put lights on timers

Everyone has seen the classic movie Home Alone, where the bungling burglars case the neighborhood and learn the residents' typical schedules. Yes, that was Hollywood, but according to Swoboda, this is a very common tactic. Burglars tend to case neighborhoods so they know exactly when to strike--and which house is likely to be empty. Swoboda's advice is to invest not just in light timers, but TV timers as well. (Intermatic makes timers that can handle large appliances.) You can set it for the times you typically watch TV (like if you never miss The Daily Show) as well as random times during the day to make the house look lived-in.