Something to do over multiple tours is to develop and tune your packing checklist.

Something from one of my first overnight tours: "make sure your brakes work".
That advice came from when I was in college, young, male and invincible. My bike was so-so and the brakes didn't always work but I could drag my feet and help get to a stop. I had organized a trip for other friends where plan was a two day trip from Boston to tip of Cape Cod and return via the ferry.

About 10 miles in, the route went through a city park and briefly on a small path. The path went down a small hill and then around a bend. My brakes weren't working and I missed the bend. The bike came to a stop and I went over the handle bars, flipped and landed on my back. It was mostly ok, except my lower right back had landed on a small rock and had an open gash. Not much bleeding, but it sure hurt.

Reasonable thing for me to have done would have been to go back home and get the back looked at. However, I was young, male and invincible and I was the leader so nobody else told me to go home. Instead someone went and bought a bandage from nearby pharmacy and we taped things up - and we continued on our way. It got hot that afternoon and I sweated into the wound (ouch!) and we bonked in heat of the afternoon. However, we eventually made our way to Barnstable and camped on a church lawn. One of my friends changed the dressing (ouch again!). Next day we eventually made our way to tip of the cape and took the ferry back.

Cycling back through Boston I felt proud to have made it, though I did learn the lesson of having working brakes...