Usually it is something with a lead time that got left until the week of departure. The flight and the hotel are rarely the problem. This page lists those things in the order they need attention, and says roughly how much notice each one takes.
Ordered by lead time rather than by importance. The first two are the ones that cannot be rushed at the last minute; the rest can usually be sorted quickly if they have been forgotten.
The single most common cause of a cancelled trip, and the one with the longest lead time. Renewal can take weeks in busy periods, and a passport that is still technically valid is not always accepted: many destinations require a margin of validity beyond the return date.
Check the expiry date rather than remembering it. People misremember by a year more often than you would expect, usually in the wrong direction.
Requirements change without much warning and are rarely the same for two neighbouring countries. Some need a visa arranged in advance, some issue one on arrival, and some require nothing at all but expect proof of onward travel.
The rule that catches people out is that these conditions depend on the passport held, not on where the journey starts. Two people travelling together can face different requirements on the same trip.
Long-distance legs are usually planned carefully; the short connections at either end almost never are. Getting to the departure point before dawn and getting from the arrival point late at night are the two moments where public transport is least likely to be running.
Worth checking the actual first and last services on the days you travel, not the weekday timetable.
Cards get declined abroad for ordinary reasons: an automated fraud check, a machine that only takes one network, a hotel pre-authorisation that swallowed the limit, a plain outage. A better card does not help. A second one on a different network does, kept somewhere other than the first.
A small amount of local currency in cash covers the gap between landing and finding a working machine, which is exactly when it matters.
Allowances differ between carriers on the same itinerary, and the restrictive one governs. On a journey with a connection, the cabin bag that was fine on the first leg is the one that gets measured on the second.
Check the dimensions of the tightest leg, and pack to that.
Treat these as rough figures. Processing times vary by country and by season, and every figure below stretches during holiday periods.
| Notice | What to deal with | Why then |
|---|---|---|
| 3–6 months | Passport renewal, visas requiring an appointment | Appointment slots, not processing, are the bottleneck |
| 1–2 months | Vaccination schedules, travel insurance, licence checks | Some courses need more than one dose to be effective |
| 2–4 weeks | Electronic travel authorisations, seat and baggage options | Usually quick, occasionally referred for manual review |
| 1 week | Notifying the bank, ordering currency, first and last connections | Enough time to fix anything that comes back wrong |
| 48 hours | Online check-in, offline copies of tickets and bookings | Checked while there is still someone to call |
| On the day | Weight and dimensions of bags, charged devices | Nothing here should be a surprise by this point |
The pattern behind the table: anything involving another organisation belongs at the top, and anything entirely within your own control belongs at the bottom. Trips come apart when that order gets reversed.
None of these are obscure, but they are the ones most often discovered at the worst moment.
An email saying a request has been received is a long way from a reservation with a reference number against it. Where there is no reference, there is usually nothing recorded at the other end.
Booking references, addresses and the first night's directions are worth having in a form that needs neither a signal nor a charged phone.
Tickets are checked against the document, character for character. A middle name included in one place and omitted in the other causes trouble at the desk more often than anything else on this page.
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The guidance here is general and deliberately unspecific about individual countries, because entry rules and processing times change often enough that any list of them would be wrong within months. Treat this page as a prompt to check the official source for your own destination and document, not as a substitute for it.