It differs depending on context. But, when I'm travelling, in order:
- Passport
- Credit Card
- Phone
Everything else is a solvable problem.
When my companions ask me to watch their stuff while they go to the toilet, I make sure they keep these three items with them just in case we get separated. Actually, everything is a solvable problem, but missing these 3 things causes big delays.
I know what you mean if I only I could swallow my passport and cards. Passport is solvable but still, I don't want to go through all trouble of replacing it overseas. And I know the problem of losing cards, in fact, all of my cards were stolen when I was traveling, ahhh, so difficult. I will probably post about it too soon.