What belongs in your personal item: an eight-thing packing list
The bag under the seat in front of you is the only one you are guaranteed to arrive with. Everything else - the checked case, and increasingly the cabin bag that gets gate-checked when the overheads fill - can be separated from you without warning. Pack the personal item on that assumption and a lost bag becomes an inconvenience rather than a crisis.
1. Documents and money
Passport, boarding pass, and the slimmed-down wallet described in the travel wallet checklist. Never in the overhead bin, never in the seat pocket, which is where documents are most commonly left behind on landing.
2. Medication for three days
Not one day - three. Prescription medication is the single thing a delayed bag can turn into a genuine emergency, and replacing it abroad ranges from awkward to impossible. Keep it in original packaging if it is anything a customs officer might ask about.
3. Phone, charger and a cable that works
The charging brick and cable, not just the phone. Airport shops know exactly how much a desperate traveller will pay for a cable. If your hotel setup matters to you, the compact version of a good one is in building a charging station.
4. A power bank, in the cabin
Lithium power banks are not permitted in checked luggage under airline safety rules, so this is not optional - it either comes with you or it does not travel. Charge it the night before.
5. One change of essentials
Underwear, socks, and a t-shirt, vacuum-flat at the bottom of the bag. It takes almost no space and it is the difference between a manageable day and buying clothes at 8am in a foreign city.
6. Glasses, contacts, and any solution
Anything your body needs to function normally. If you cannot read a departure board without them, they do not go in the hold.
7. Keys, folded flat
House keys travel with you, because the alternative is arriving home at midnight unable to get in. A key organizer is worth more on a trip than at home: keys that cannot splay do not tear the lining of a soft bag or scratch a laptop sharing the same compartment.
8. A tracker in the checked bag
This one is not in your personal item, but it belongs on the list, because it is what makes the rest of the strategy work. A tracker tucked into the checked case tells you where it actually is while you are standing at a baggage desk, which materially changes that conversation. The rest of the process is in what to do in the first 24 hours.
What to leave out
Anything heavy that you will not use in flight. A second book. The laptop, if this is a holiday and you know perfectly well you will not open it. Full-size toiletries. Every one of these gets carried through four terminals for nothing.
The test
Pack the personal item, then ask one question: if my checked bag arrives two days late, what do I actually need to buy? If the answer is nothing important, the bag is right. If the answer includes medication or documents, repack.