Look at my bag (the one on the left) as I enter China sometimes in late 1990s. I used to get carried away and pack everything that I might need. Over the years, as I discover new fabrics, technology etc, and as I learn to live with less and less stuff, I have been trimming what to carry. This is my current arrangement.
Most important is the bag. The brand doesn't matter as long as it is somewhat waterproof and sturdy.
The stuff inside, I use mesh case for packing sundry stuff, as some airport security wants to visually inspect stuff and mesh is a good material to pack razors, tooth brush and moist swimwear, helping them dry faster.
- one case for the charger and cables, keys, currencies and cards for other destinations
- one case for toiletries (some airport security like to able to visually inspect stuff)
- one case for swimwear
- the larger case packs one or two change of clothes
- a notebook - doubles as storage for tickets, maps etc
- iPad for writing and presentations
A phone and a custom made wallet go into my pocket. I usually get a inner pocket stitched on my trousers for safe keeping the passport, some cash and a spare bank card.
Light, quick drying clothes are my favourites. Uniqlo's easy pants and Muji's Indian cotton shirts complete the sartorial department. The maximum I carry is two change of clothes (in addition to what I am wearing). I experimented a lot with different fabrics and brands finally settled on these for their easy availability across East Asia, and the fact they dry in a couple of hours.
The bag with all the stuff inside weights less than 4 kilograms. Carrying a small bag makes you more mobile, you can get in and out of the flights, trains faster. If I need anything beyond this, I usually buy them locally at a supermarket.