Even with a valid passport, you can be barred from certain countries, such as Switzerland, that require travel documents to be good for at least three months after your planned departure.
Before you book that international trip, make sure to check your passport—you can be barred from entering some countries if it's expiring in the next several months.
Even popular destinations such as France and Switzerland have rules about passport validity, and they're increasingly enforcing them. France mandates that your have at least six months left on your passport when you arrive, and it has to be valid for at least three months after your scheduled departure. Switzerland says your passport needs to be good for at least three months after you plan to leave.
The U.S. Department of State website has comprehensive information about each country's passport and visa requirements. It also has a tool that helps you center and resize passport pics. Or, you can try one of the new apps that help you renew.