Travel

2. Their software doesn’t always hook up to the hotel’s system.

A guaranteed reservation is almost impossible to come by—but the risk of finding out your flight or hotel is overbooked increases with third-party providers. The middleman’s software isn’t immune to system errors, so always call the hotel or airline to make sure your booking was processed.

3. Don't be fooled by packages: Often, they're low-end items grouped together.

Ever notice how travel sites recommend one-stop shopping, like a hotel, rental car, and tour package all in one click? These deals usually feature travel that no one wants, like flights with multiple layovers. Check the fine print.

6. You aren't likely to build airline or hotel loyalty.

7. Travel agents often can share exclusive perks.

Online booking sites are all about dates, rates, and space, meaning their goal is to put heads in beds, says Misty Ewing at Virtuoso luxury travel network. But for the same price, an agent might have connections and special access. “For example, when traveling in Italy, you can take a cooking class with a local resident in her home—a level of authenticity not provided by the Internet,” she says.

8. Corporate travel needs are probably better done in person.