One of the simplest ways to ensure a great vacation is having all the proper documentation. Everybody knows you need a passport to travel internationally, but several countries also require U.S. citizens to have visas to enter. For residents of certain states, it’s domestic travel that might get a lot more complicated in the coming year, thanks to varying degrees of compliance with the REAL ID Act. The last thing you want to do is show up at the airport and be surprised to learn you don’t have what you need. You can always buy a toothbrush if you forgot yours, but if you don’t have the proper identification, you’re in real trouble.