Packing a lighter first-aid kit
My old kit was a brick of things I would never use on a day walk. Rebuilding it around what actually goes wrong cut the weight by two-thirds.
Blister care, tape, painkillers, antihistamine, a couple of large dressings and a foil blanket cover almost everything a day out throws up. Anything worse and the plan is to get help, not to perform surgery on a hillside.
The one addition I kept was a small roll of duct tape wrapped around a pencil. It has fixed boots, poles and a torn pack far more often than it has fixed me.