And if your trip goes a little awry (like the 10 hour layover I suffered through in Newark last week, when my flight was delayed due to weather), there are a few extras you'll wish you had brought along.
The American Express Small Business site recently described 18 must-haves for the business traveler. Many of their recommendations are already a standard part of my packing list. Others are interesting ideas that I am seriously pondering adding to my load-out. Here are my favorites (read the article for the whole list):
1. Medication. Obviously, it's a good idea to bring along any prescription medication you need. But some aspirin, motion-sickness pills, and the like can also be a lifesaver.
2. Travel pillow. I would have loved a small pillow for my 10 hour marathon sitting experience in Newark's Concourse C last week.
3. Power adapter and voltage converter. Get a universal adapter for international travel -- that way, no matter where you go, you're covered.
4. Water bottle. You need to stay hydrated on every leg of your trip, not just the airport. So carry a water bottle and keep it filled. And carrying a water bottle means you can fill it from a water fountain after passing through security, avoiding the need to constantly buy $3 bottles of name-brand water.
5. GPS. Did you know that it can cost as much as $15/day to get GPS in a rental car? Forget that; you can bring your own for a lot less. The most convenient solution is to get navigation software for your smartphone.
6. USB Flash drive. Sure, you can probably store most of what you need in the cloud with DropBox or SkyDrive, but nothing beats the tactile convenience of carrying an 8GB flash drive in your pocket. It always works, whether you have Internet access or not.
7. Wireless mouse. I hate trackpads and pointing sticks. If you are going to use your laptop for anything more than a paperweight on your trip, you owe it to yourself to carry a wireless mouse.
8. Noise-cancelling headphones. These are a lifesaver. Bring a set of noise cancelling headphones to help drown out the din of airport chatter, airplane engines, babies crying, and Cloverfield monsters. This, in fact, is perhaps the most important thing to carry -- I'd sacrifice my medication for the right pair of headphones.
Did I miss anything important? What do you carry on your business trips?
Update: For your convenience, I've collected all the reader comments and organized them in Prep for Your Next Business Trip: What Readers are Packing.