Paperwork is the least interesting part of travel and the only part that can end a trip at the check-in desk. It takes about thirty minutes to get right and it is worth doing early, because several of these items have lead times.
Passport validity
The common rule is six months of validity beyond your date of entry, though it varies. Some countries require three months beyond your intended departure. Airlines apply the destination's rule at check-in, and they are strict about it because they carry the cost of returning you.
Visas and travel authorisations
There are three broad categories: visa free entry, an electronic travel authorisation obtained online in advance, and a full visa requiring an application. The middle category has expanded significantly in recent years and it is where people get caught, because it feels like visa free travel until an airline asks for the reference number.
- Check the destination government's official immigration site, not a third-party service
- Apply at least two weeks ahead for electronic authorisations, longer in busy periods
- Note that transit through some countries has its own requirements

Proof of onward travel and accommodation
Several countries require evidence that you intend to leave, and immigration officers may ask for your first night's accommodation address. A printed copy of a booking confirmation resolves this in seconds.
Driving abroad
An International Driving Permit is required in a number of countries and is issued by an authority in your own country before you travel. It cannot be obtained abroad. Check whether your destination requires one, and check whether your rental company requires one even if the law does not.

Copies and backups
Keep a photograph of your passport and any visas in a location you can access from a borrowed device. Email them to yourself if nothing else. Carry one printed copy separately from the passport itself. If you lose the original, this shortens the replacement process considerably.
Requirements change with little warning, so the final check should be a week before departure rather than only at booking time.
Confirm entry rules with the destination's official source before booking.
