I always have a knife. A little SA Classic is always in my pocket. That little sucker has tweezers, toothpick, screwdriver, file, blade, all in a dinky package. It's amazing how many times I hear "does anyone have a knife"?
I also usually have fire, even though I've never smoked. A book of paper matches in my wallet will be used up by the end of the year.
I never carry sunscreen goo....hate the feel/smell of it. I tend to wear my sun protection instead.
I've never thought in terms of "essentials", ever. The trip dictates the need and I tend to prioritize stuff instead.
Shelter, warmth, food, hygiene, and a plan.