Travel planning is a science, and many travelers have mastered the art of booking plane tickets, buying new gear and mapping out their itinerary. But you might be making some costly missteps and not even realize it. Here are the six biggest mistakes you might not know you're making.

Not Trying Out Your New Gear

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You’ve bought all the gear you need for your trip, and you’ve tried on the new hiking shoes, backpack and rain jacket. But just trying it on isn’t enough — have you tried it out? Before you can determine whether your gear is truly good to go, you need to test it in the real world. Find a way to simulate what you’ll be doing on the trip so you can use your new gear before you leave. If you’re planning to spend your vacation walking around a European city, go for a prolonged walk around your own city wearing your new shoes to make sure you don’t get blisters. If you’ll be hiking in South America, suit up with your new backpack (plus everything you’re planning to carry in it) and do a test hike on a local trail. You’ll thank yourself when you arrive at your destination.

Booking Flights Too Far in Advance

Yes, it’s important to not wait until the last minute to book your flight — but some travelers actually have a bad habit of booking flights too far in advance. Why is this a bad idea? In short, you might not get the best price. According to AirHelp, booking too early is the #1 mistake travelers make. “The cost of booking too early can sometimes be as high as booking too late,” the article said, adding that the sweet spot is one to three months before departure for domestic flights. The other downside of booking flights too far in advance is risking your plans changing. Whether it's bad weather, an unexpected family event or something else causing you to change your plans, you could be liable for some hefty change or cancellation fees if you book too far out.

Not Learning About the Local Culture

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It’s essential to be respectful of local cultures when you’re traveling, but you can’t respect traditions if you don’t know what they are. Do some research on the Internet or talk to someone from the country where you’ll be traveling. This can help you figure out how you’ll be expected to behave when you arrive. Is it respectful to cover your knees in the local landmarks? Is arriving a few minutes late considered rude? What about tipping? You need to ask all of these questions before you leave, as the answers might affect how you pack.

Not Reading Reviews

Booking a hotel? Going to a pricey restaurant? Hitting up the local tourist attractions? Before you make any definitive plans, read reviews! Sites like TripAdvisor or Trivago have plenty of reviews from other travelers. Whether or not you’re on the fence about adding something to your itinerary, go ahead and read some reviews anyway. The attraction’s website is designed to make it sound good, so instead, check out some third-party reviews from travelers who have been there.

Not Strategically Packing Your Carry-on

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A change of clothes, prescription medicines and any valuable or valuable-to-you items need to be in your carry-on, not your checked luggage. Airlines are 70% less likely to lose suitcases than they were 10 years ago, but still, you don’t want to be part of the small percentage that still suffers. Being caught in a foreign city without clean underwear and medicines you need to function is a recipe for disaster, so put anything in your carry-on that you might need.

Not Alerting Your Bank You’ll Be Traveling

If you begin using your debit or credit card as soon as you land, your bank might see the charges racking up in a foreign city and freeze your account. To prevent this from happening, let your bank know that you’ll be traveling before you leave. “When you let your bank know that you’re going away, they add a record to your account and share it with their fraud detection system,” said Western Union. Most banks make it easy to notify them with an online system, and you’ll be able to shop in peace.