Millions go on vacation each summer; some simply want to soak up the sun, and others look forward to a wintry escape from the heat, while exploring new vistas.

But absence leaves your household security at risk, and thieves are adept at spotting the signs you're not at home.

1. Social Media Check-Ins

If your privacy settings aren't up-to-date, strangers could view your profile on Facebook. And even if only friends can see your online activities, you're still vulnerable. As sad as it is to say, some thieves are people you know.

Facebook encourages you to "check in" when you're away from home, be it in foreign climes or at the cinema. You don't have to be the one checking in, either. Someone you're with might pinpoint your location online! Needless to say, this is a major indicator to burglars that your house is empty.

It doesn't need to be on Facebook. You might be excitedly talking about being at the airport on Twitter, or tweet about buying luggage for an upcoming break. #RookieError.

What can you do about it? Don't feel the need to let everyone know where you are and what you're doing all the time. Who cares? It's seriously not worth it.

It's very easy to stop people tagging you too. All you need to do is go to Settings > Timeline and Tagging Settings. From there, you can lock down your profile so you're the only one with the permission to post to your timeline. This includes check-ins. While you're in Settings, review previous tags and who can see them.

2. Vacation Photos

Criminals might connect the dots when you post a stunning picture of a beach with the caption "I Heart Hawaii!"

In much the same way as tagging, images of far-off lands alert thieves that you're away from home. These photos might be on Twitter, Tumblr, Instagram, or even Snapchat: it doesn't matter.

It seems fair to assume people on social media won't know where you live. However, with the wealth of Personally Identifiable Information (PII) available---and at a low cost on the dark web---it's actually not difficult to link online profiles up with real-life data. Goods stolen in burglaries often carry considerable costs, so some research is worth it for the bad guys.

What can you do about it? If you really want to share where you've been with your family and friends, be patient. Just wait until you're safely back home to post those holiday pics!

3. Metadata

You may figure that you can take a shot of dinner without anyone knowing you're abroad. In some instances, you'd be right. But certainly not in all circumstances.

Your images can include metadata, often as Exchangeable Image File Format (EXIF). This means there's a hidden layer of information lurking in your snaps, notably a time- and date-stamp and location.

If you upload something to Twitter, the service removes this metadata. In fact, most get rid of all EXIF info. But not all of them. Perhaps the most notable of these is Flickr, which boasts details on your camera's settings.

What can you do about it? Again, be careful only to share images when you return home. Be wary, even if you think a site strips metadata anyway. Some depend entirely on the method you used to take the shot; PC uploads frequently retain EXIF while smartphones generally don't.

It can be a bit fiddly, but it's worth knowing how to get rid of metadata in your photos.

4. Amazon Shopping

When you order something from Amazon, the company will prompt you to share your latest purchase on social media. It's a way of generating free promotion for the site.

It's not always a good idea, though, particularly if you've ordered travel guides, maps, or sun tan lotion.

You might not think this anything major (it doesn't tell anyone when you'll be out of the house exactly), yet it's a signifier which could mean criminals will start paying more attention to you.

This is similarly true if you have a public wishlist featuring many items associated with vacations.

What can you do about it? Firstly, make sure your wishlists are private because by default they're not! Alternatively, you can try out a different wishlist service, like these great extensions. Criminals are less likely to target smaller companies than the tech giant, Amazon.

Keep your potential purchases private, especially if they're related to a holiday. This can be annoying if you've set up a wishlist for a honeymoon or birthday trip, but why risk it? You could simply tell people face-to-face or by SMS what you've got your eye on.

5. Mail and Trash

Your online orders aren't the only indicators that you'll be away from home.

Hopefully, you realize the risks of putting private details in the garbage. It's first and foremost a way criminals can steal your identity. Some personal documents can advertise an upcoming vacation, too.

Notably, you need to be careful when throwing away bills and statements, particularly when these include payments to travel agents. That's not all: medical identity theft is a massive issue, made worse if you've recently had vaccinations for going abroad.

However, burglars are audacious---they not only scour through your trash, but also attempt to intercept your mail.

What can you do about it? Shred anything with private data on before it goes in the garbage. We recommend cross-shredders to do the job properly.

How can you prevent mail theft? You need to be astute: empty your mailbox as frequently as you can. And if you're expecting notifications from your bank but don't receive anything, follow it up. You could also switch to online banking, which cuts down on the need for physical statements and documents.

6. Lack of Lighting at Home

Once thieves know someone is due to go on vacation, they'll look out for unusual activity. Or inactivity. Because a home with no lights on in the evenings is, ironically, like a beacon, telling people that house is empty. Sometimes, when houselights aren't on, people rely on illumination from the television; if a criminal can't even see that, it's a further sign that a property is unoccupied.

Never underestimate the patience of robbers!

What can you do about it? Timers aren't fool-proof, but they're at least a good start. Use them for your lights, but anyone who's seen Home Alone will know that thieves can recognize their schedules.

Home automation gives you the power to control aspects of your house even when absent. Smart devices allow you to turn lights on and off, and make sure your house is ready for your return by switching on the heating!

That might seem an expensive option, but cheaper ones exist too. For instance, Fake TV makes it look like your television is on, which is certainly a neat invention.

7. Unusual Behavior Patterns

Don't change your normal patterns or break them completely while you're travelling. It relates back to using timers: you need any fail-safes you set up to be roughly in line with what you normally do.

Though a casual thief probably won't notice that, they will catch you out if your lights go out too early or late based on the season. That's without mentioning a more attentive criminal who keeps a note of what people in the neighborhood are doing.

What can you do about it? Everyone has a routine, so try to keep "business as usual" while you're away too. If you don't typically go to bed until 11pm, set your lights to turn off around that time.

You could use solar lights, so they only come on when it gets dark. This is especially useful in spring or fall, when the changes in daylight shift quickly across a week.

Take Care and Don't Worry Too Much

In the US, a home break-in occurs every 13 seconds. But even with that in mind, it's still pretty unlikely you'll be a victim of this sort of crime. (In fact, the fastest-growing crime in America is actually identity theft.)

It doesn't take a great deal of effort or money to secure your home. There's no reason to worry. Don't let anything stop you enjoying your well-deserved vacations.