I carry enough clothes for the length of the trip plus a day or two spare. And a small washbag, usually. A phone charger. My meds so I don't die, and a book for the transportation.

I've only needed the spare clothes once, and I was really smurfing glad i took them, even if they do take some space!

I also (used to) travel for work pre-pandemic which meant all of the above plus a bunch of computer trout, which really sucked to drag around.