What to do if the airline loses your luggage

1. Go to the airline's baggage service desk in the arrivals hall, before customs if the layout allows it. Not the check-in desk, and not a phone line.
2. File a report and get the written reference number. Airlines issue a file or property irregularity reference. Without it, nothing that follows exists as far as the airline's system is concerned.
3. Give a description, not just a brand. Color, type, any distinguishing mark, and what is in it. A black 22-inch spinner is not a description; a black 22-inch spinner with a red ribbon on the handle is.
4. Give the address you will actually be at, not your home address, and a phone number that works in the country you are in.
5. Photograph the file reference, the tag stub and the desk agent's name. This takes ten seconds and is the thing you will wish you had in a week.
6. If you have a tracker in the bag, screenshot its last location with the timestamp visible. A timestamped screenshot is far more effective at a baggage desk than a live app you have to explain.
7. Ask what the carrier's interim expense policy is, and whether they will pay directly or reimburse. Get the answer in writing if you can - the policies differ and so do the caps.

One thing not to do: do not accept a verbal assurance that the bag will arrive tomorrow in place of filing the report. The report is what starts the clock on every entitlement below.

Three separate entitlements apply, and they are often confused with each other. These are the published figures for flights to, from and within the United States.

The DOT defines a significantly delayed checked bag as one not delivered to or collected by the passenger "within 12 hours of the last flight segment's arrival for domestic itineraries, within 15 hours ... for international itineraries with a non-stop flight segment between the United States and a foreign point that is 12 hours or less in duration, and within 30 hours" for longer international segments. Cross those thresholds and the bag fee is refundable.

• The liability limit is per passenger, per incident - not per bag. Checking three bags does not raise the ceiling.
• Compensation is subject to depreciation. You are being paid for the current value of used clothes, not their replacement cost, which is why itemized receipts for what you actually bought matter more than a list of what you lost.
• Declaring excess value at check-in raises the ceiling, for a fee, if you are carrying something genuinely valuable in a checked bag. The better answer is usually not to.
• The limits are maximums, not entitlements. Airlines pay against a documented claim, which is the entire argument for keeping receipts.

1. Buy what you reasonably need, not what you would like. Underwear, a change of clothes, toiletries, a phone charger. Reasonable and verifiable is the standard a carrier applies.
2. Keep every receipt, itemized. A card statement line is not a receipt. Photograph each one as you get it, because thermal receipts fade.
3. Check the carrier's online baggage tracker daily and screenshot each status change. A documented record of a bag sitting in one place for four days is useful at a claim stage.
4. Escalate in writing after the carrier's stated delivery window, not before. A written escalation with a file reference attached is handled differently from a phone call.
5. At the point the airline declares the bag lost, file the itemized contents claim. Carriers set their own deadline for this, usually a short one, and it is stated in the conditions of carriage.
6. Check your travel insurance and your credit card's benefits separately. Both frequently cover baggage delay above what the airline pays, and both have their own filing deadlines.

Carriers generally declare a bag lost rather than delayed somewhere between five and twenty-one days, and the figure is published in each airline's own baggage policy - check yours rather than assuming a number.

Nothing on this page prevents a bag going missing. Three things change what happens next, and all three are cheap.

• A tracker inside the bag. It will not stop the bag being lost. It changes the conversation from you asking an airline where your bag is to you telling them, which is what shortens a three-day delay to a one-day one. Inside the bag, not on the outside.
• A luggage tag with a covered window. The tag is what gets a bag back from whoever eventually finds it, and a covered window means a baggage agent can read your details while a stranger at a carousel cannot.
• One change of clothes in your carry-on. This is the single highest-value habit in travel. Underwear, a shirt and a toothbrush in the cabin bag removes the worst day of a delayed-bag trip entirely.
• Nothing irreplaceable in the hold. Medication, documents, electronics, chargers and anything you would not insure belong in the cabin - what not to pack in checked luggage covers both the prohibited items and the merely unwise ones.
• A photograph of the packed bag, taken before you close it. An itemized contents claim is far easier to write against a photograph than against memory.