B is for Backpack
Carrying your photo kit and any other essentials you need through the day is an art in itself. A backpack spreads the weight over both shoulders to make heavier loads more comfortable, and it allows you to organise your photo and non-photo gear into different compartments so everything is easy to find. Many backpacks are designed to stay within cabin baggage dimensions, so you can keep your essentials with you.
While packing, assume your hold baggage could get lost, and carry the stuff you really need in your backpack. That’s your camera kit, travel docs, toiletries, spare underwear and a waterproof jacket. You can survive on that for a week!