In the past few days a couple of my friends found themselves in quite a dilemma when it came to flying to Europe with a passport that, while not yet expired, did expire in early 2020. Even if your passport is not expired, that does not mean you are guaranteed to be able to leave the U.S. if your card has an expiration date within three to six months of your flight back home from Europe. Below is a cautionary tale that even frequent fliers can sometimes make an error that could cost them their trip abroad. Thankfully I have an organized wife who writes everything down, or I'm sure this would have happened to me at some juncture of life.

https://travelswithmaitaitom.com/get...airs-in-order/

The EU states your non EU passport must be valid for three months after your intended date of departure from the EU. Plus ETIAS from 2021.
The US requires 6 months from date of departure from the US. Plus ESTA
A passport cannot be valid for more than 10 years, so you can no longer renew early and get the time added to your new passport as used to be the case in the UK.

Some countries also require that your passport have at least 2 blank pages before they'll grant you entry.

Australia requires at least 6 months validity to be able to travel.