Americans stink at planning vacations.

And that includes our commander in chief. President Trump forgot to book a hotel room in Hamburg for his trip to the G20 summit this month. By the time the Trump’s staff began searching for a reservation, Buzzfeed reports, every luxury hotel was sold out.

Luckily for Trump, the city found him shelter in a senate guest house. But you probably wouldn’t be so lucky. And, indeed, experts say there are a ton of travel mistakes that many Americans make that are costing them a pile of money. Here are four.

Mistake 1: You’re not looking at the right booking sites
Expedia and Travelocity may sometimes have the best deals on flights and hotel rooms, but they don’t always. You should be looking at every booking site you can to find the best price for your flight and hotel room, says George Hobica, founder of Airwatchdog.com.

“There’s a myth out there that says you can just go to the hotel’s website and get the best price,” Hobica told Moneyish. But he recently saved $175 on a hotel room in Boston, because one website was much cheaper than the others. Kayak, Momondo, Skyscanner, and Airfare Watchdog are among the best sites to find deals on hotels and flights– though it’s important to remember that Southwest, one of the cheapest U.S. airlines, won’t show up on any booking site, as it only sells tickets from its website.

Additionally, try different browsers, says Gabe Saglie, senior editor of Travelzoo. You may get better deals in Firefox or Safari than you will in Chrome. And don’t book on your phone–it’s easy to make mistakes.

Mistake 2: You assume your hotel rates will stay the same
Sometimes, the price of your hotel room will stay the same after you book, but sometimes it will change. Check with your hotel right before you arrive to inquire about your rate, and re-book your room if it’s lower than what you reserved. (Some hotels won’t let you cancel after a certain time, so make sure you check.) The website RoomsNinja.com will also track your reservations for you, and invite you to re-book when the price has reached its lowest point.

Mistake 3: You don’t use your free travel insurance
Travel insurance comes as a free perk with a number of credit cards, and can be a lifesaver for a traveler. Your plan will likely ensure that various travel mishaps, such as lost or delayed baggage, flight delay, or last-minute cancellation don’t ruin your trip or your finances. Through Hobica’s plan, his credit card company reimbursed him for a $400 item that he lost on a plane. If you’re a frequent traveler, getting a credit card with free travel insurance could save you significant money.

Mistake 4: You’re booking all your plane tickets at once
If you’re flying with family or a group of friends, you’re probably tempted to book all of your seats together. Hobica’s recommendation: Resist. Most booking sites will only show groups of tickets that are all the same price, and since cheaper tickets are available in lower quantities, the more tickets you try to book at a time, the higher your prices will be. Flights often have only one or two tickets available at the lowest possible price; by booking your group’s tickets one at a time, you’ll be making sure you scoop those discounts up.

Mistake 5: You’re not reading the fine print
It’s easy to dash for what looks like a killer deal. But hotels and airlines often have hidden fees that will hike up your price. Check your hotel’s terms and conditions for their minimum length of stay, cleaning fees, key fees, and other costs they might be hiding. And budget airlines such as Norwegian, Spirit, and Frontier will charge you for bag checking and other services you may take for granted.