The largest avoidable costs on most trips are not flights or hotels but a set of small percentages applied repeatedly. Three decisions, made once before departure, remove nearly all of them.
1. Always pay in the local currency
This is the single highest-value habit in travel and it takes one second per transaction.
When a card machine or ATM abroad asks whether you would like to be charged in your home currency, it is offering dynamic currency conversion. The rate is set by the terminal operator, not your bank, and it is consistently 3 to 7 percent worse. The screen presents it as a convenience and a certainty; it is a markup.
Always choose the local currency. Euros in Europe, yen in Japan, baht in Thailand. Your own bank then converts at a far better rate.
This applies at ATMs too, where the prompt is worded as "with conversion" versus "without conversion". Choose without.
Cards, briefly
Carry two from different providers, stored separately, so one blocked or swallowed card is an inconvenience rather than a crisis.
Look for a card with no foreign transaction fee — most travel-focused accounts now offer this, and the 2.75 to 3 percent that ordinary cards charge on every purchase abroad adds up faster than people expect over a two-week trip.
At ATMs, prefer machines operated by actual banks. The standalone machines in airports and tourist streets charge high fixed fees and push DCC aggressively. Withdraw larger amounts less often so any fixed fee is spread.
2. Data: eSIM versus roaming
Within the EU, most European mobile plans include roaming at no extra cost, and an eSIM adds nothing.
Outside your home region the picture reverses. Pay-as-you-go roaming can be several pounds per megabyte, and a single day of casual map use produces a memorable bill.
A travel eSIM typically costs $5–20 for several gigabytes over one or two weeks, installs before you leave, and activates on landing. Any recent phone supports it, and you keep your home number active for messages while data runs over the eSIM.
Check your phone is carrier-unlocked before relying on this.
3. Insurance: read the exclusions
The headline benefits across policies are nearly identical. The exclusions are where they differ and where people discover they were not covered.
The three that catch travellers most often:
Motorbikes and scooters. Excluded unless you hold a licence valid for that engine size in your home country, and often unless you wore a helmet. This is the most common uninsured claim in Southeast Asia and southern Europe, and rental shops hand over bikes without checking anything.
Adventure activities. Skiing, diving beyond a depth, trekking above an altitude, climbing — all usually need a paid add-on.
Pre-existing conditions. Must be declared. An undeclared condition can void medical cover entirely at some insurers, including for unrelated events.
What actually matters in a policy is medical treatment and repatriation. A cancelled flight costs hundreds; a medical evacuation costs tens of thousands. Weight the cover accordingly rather than by baggage limits.
The small ones worth knowing
City tax is charged separately at check-in across most of Europe, €1–5 per person per night, often cash, and never in the booking price.
Airline seat and bag fees are cheaper bought online in advance than at the airport, sometimes by half.
Airport transfers are frequently the worst-value line in a trip. A regulated flat-fare taxi or a train is almost always better than a hotel-arranged transfer.
None of this is exciting. It routinely amounts to more than the saving from a cheaper hotel.