I've been going lighter and lighter and am down to a backpack that I carry (mostly just meds and electronics) and a small suitcase that I could carry-on, but I usually check. But my spouse packs heavier and heavier every year. It's a way to cope with anxiety; you think of everything that can possibly go wrong, and you make sure you have that mitigated with something in your carry-on.

And that's why on our last trip we had 9 pounds of dog food for our service dog, in cold packs, in our carry-on. "But what if there's a problem with the flight, and we lose our luggage, and we can't get to a pet food store for the whole two weeks?"

Spoiler: The cold packs didn't last, the food spoiled, and we had to go to a pet store.