As it turns out, that depends on where you’re planning to travel. Each country sets its own requirements as to how long your passport should remain valid, and some won’t even let you board your flight if there’s less than six months to go, despite your passport being perfectly valid.

Australia, for example, allows its citizens to use Australian passports for all travel to and from Australia right up until the passport’s expiry date, the Department of Foreign Affairs and Trade confirms.

But many other countries aren’t that generous, which can render your 10-year passport useful for 9.5 years at most!

Why do some countries have a ‘six-month validity’ passport rule?

While the reasoning varies between countries, having a valid passport not only allows you to leave the country you’re visiting but also enables you to return home or continue your travels, without getting ‘stuck’ anywhere without a valid travel document.

In case of any medical emergencies, not having to unexpectedly renew a passport overseas represents one less hassle to deal with, either when your travel dates need to be extended for urgent hospital care, or if there’s a sudden need to evacuate you to another country for treatment, which may have its own passport validity requirements.

Having a passport that’s valid beyond the dates you originally planned to visit also makes things easier for immigration officers if you overstay your welcome, as you can be immediately deported from that country on your valid passport, rather than having to stay for several days more while you apply for a new one.

However, there’s no denying that the ‘six-month rule’ can be bothersome for business travellers planning a routine trip, from which they’d be back at home many weeks or months before their passport expires.

European Schengen Area countries (France, Germany etc.): Technically, your passport only needs to be valid for three months beyond your intended stay, but some countries may assume you’ll stay for up to 90 days as your entry permit may allow, so having a passport valid for six months from the date you arrive avoids any unnecessary issues at the border.

United Kingdom: Australian passports need only be valid for the duration of stay, and for your onward travel arrangements, subject to the passport rules of your next destination or transit point.

United States: While the USA normally requires passports to be valid for six months beyond the traveller’s intended stay, Australian travellers are exempt from this requirement and instead only need a passport that’s valid for the for the duration of their intended stay (and to travel home).

China: In order to apply for a Chinese visa, Australian passports must have at least six months validity remaining.

United Arab Emirates (Abu Dhabi, Dubai): Passports must be valid for at least six months from the date of entry into the UAE, or for three months from the date of travel for those merely transiting the country without crossing the border.

Qatar (Doha): To enter Qatar using the visa-on-arrival process, an Australian passport must be valid for at least six months from the date of entry.

Singapore: Australian passports must remain valid for six months beyond the dates of your intended stay, even when you’re just transiting – such as on QF1 from Sydney to London via Singapore, where you don’t even clear Singapore passport control.

Hong Kong: Passports must be valid for at least one month beyond the dates of the intended stay.

As always, it remains the traveller’s responsibility to independently confirm that they meet a country’s entry requirements, remembering that these may change from time to time and can vary for passengers of varying nationalities, or using different types of passports or travelling on certain visas.