When traveling outside of America, a Passport is required for the majority of countries you will be visiting. It is important to have a Book that not only has a long expiring date, but also many pages.
My Passport is almost out of room because of my travels through Egypt, Jordan, and Israel, not to mention layovers like Vienna. I only have a few years left as I got it back in 2010. I believe that passports usually expire in 10 years.
Before I go, I will apply for a new Book and request the 52 page option. This is free of charge.
An American citizen may have multiple passports, so I plan on utilizing both of them for longer stays and less worries. Sure, it will weigh me down slightly, but it is worth it in the long run.
If you are planning to visit several countries for longer periods, I suggest opting for the multiple pages, and possibly multiple Books.