>>2826974There are a million "useful" things to bring that are never used. Another saying is "don't pack your fears", all the what if I need this or that, what if this or that happens...
Start by dividing everything into systems. Sleep system, cooking system, clothing system.
Figure out what you actually need and use for each system.
How do you sleep? Tent, tarp, car, hammock? Do you need a sleeping bag? What temperatures does it need to handle? Sleeping pad or cot? Pillow? Etc.
Gear and it's specific properties become more important when you're doing longer hikes unsupported and/or need to protect yourself from the environment.
One of my favourite useful gear is a merino wool neck tube/scarf. Pic rel. Thin, light and keeps you warm.