I am re-posting it here. I don't agree with everything, but most is overall solid.

I would have at least four times as much underwear and socks. Never can have enough. Worse case, you can stretch it out and wear the same jeans an extra day. But, a fresh shirt once or twice daily will make you feel better.

Various stuff to handle various climates. Could be hot/dry or cold/wet. Layers, hats, gloves, coats/jackets, etc.

Keep all valuable documents and stuff together in a fireproof case. That way, you can just grab the case.