One day at one of the albergues I was staying in, a fellow pilgrim came rushing in, holding a pair of pants in his hand and yelling "WHO STOLE MY PANTS??!! WHO STOLE MY PANTS??!!!!!" Those of us who were enjoying dinner, looked at each other puzzled. It took me a few seconds for me to realize that he was holding MY hiking pants in his hands, a pair I had washed out and which I left drying on the clothesline. I put my fork down and followed him as he raced from room to room, looking for his pants, holding mine hostage. He was using my pants to show what his pants looked like. I got my pants back. His pants had been moved to a different part of the clothesline by a couple of good Samaritans who didn't want them to get all wet from a rainstorm which had just moved in. Instead of assuming the worst, he should have just reviewed the situation. A calm glance would have saved him a bit of panic, but the rest of us, including me, would not have had such a good laugh at his expense.
Keep the things that you absolutely cannot replace close at hand all the time - Camino photos, credencial. Keep those things that would be a pain to replace, within sight all the time - passport, money, credit cards, electric tools (phone, iPad, etc.). Everything else, use common sense and trust the Camino (and your fellow man) to take care of you. You can't be looking out for your stuff 24/7, sometimes you just have to let go.
The only thing I lost was a comb, which I left at the albergue on day one (took me 3 days to find a store to buy another) and the rubber tip from one of my hiking poles - it got sucked off by the mud. LOL!