Pack lighter for an easier trip: why bags get heavy, three days of clothes, what you cannot forget, cabin versus checked bags and a night-before checklist.
Things packed 'just in case' end up filling half the bag. That case rarely arrives, and when it does, the item is usually available locally. One rule simplifies it: if it is easy and cheap to buy there, leave it behind. A surprisingly effective method is to lay everything out on the floor first and then remove a third of it. Noting the items you never used once you are home gives you a baseline for the next trip.
Even for a week, three or four days of clothing works. Do one wash midway; without a machine, underwear and socks hand-wash easily. Keeping colours coordinated multiplies the combinations and cuts the count. Wearing your bulkiest layer on the plane lightens the bag noticeably. Shoes take up the most space and weight, so wear one pair you can walk in all day and add light sandals only if you need them.
Clothes can be bought there; these cannot easily. Chargers and plug adapters, your regular medication, a copy of your passport. Prescription medicine in particular is hard to match abroad, and an English-language prescription makes customs conversations simpler. For a basic medical kit, painkillers, something for indigestion and a few plasters in a small pouch is enough. Some countries restrict certain medicine ingredients, so if you take long-term medication, check the destination's rules. Keep passport copies in several places, such as one paper copy, a photo on your phone and a copy in cloud storage, so a replacement goes faster if it is lost.
Anything whose loss would end the trip goes with you. Passport, cards and cash, medication, electronics, one change of underwear. Checked bags arriving a day late is not rare, so whatever you need on day one must be in the cabin. Liquids in the cabin are limited to 100ml per container. Liquid rules can also depend on the screening equipment an airport uses, so check the latest guidance for both your departure and transit airports.
Keep space for souvenirs and whatever you buy there. A full bag on the way out means excess baggage fees on the way home. Packing one foldable bag is an easy fix. Liquids bought duty-free may be screened again at a transit airport, so keep them in the sealed bag with the receipt. Duty-free allowances and import rules differ by country and can change, so check them before you head home.
Lithium batteries such as power banks generally cannot go in checked baggage because of the fire risk; they travel in the cabin only. Depending on capacity, the number you can carry may be limited or need airline approval, and more airlines are banning their use or charging on board. The rules vary by airline and change often, so check your airline's notices before you fly. One universal adapter and a charger with several ports make life easier in rooms with few sockets.
Checked-bag weight limits and excess fees differ by airline and fare. To avoid repacking in front of the check-in desk, weigh the bag at home. Without a luggage scale, step on a bathroom scale holding the bag and subtract your own weight. Bags usually get heavier on the way back, so leave a margin on the way out. Low-cost carriers may also weigh and measure cabin bags strictly.
Checking just these items before you zip the bag avoids most disasters. Look separately at what must be in the cabin bag and what can go in the hold.