Everytime I walk out the door, I have my wallet, keys with a Fenix L0P and a Victorinox Manager swiss army knife. These are the only things I have in my pockets.

I supplement with other things depending on where i'm going. When walking to work, I carry a Leatherman Juice S2 multi-tool and a Bic lighter in a Samsonite messenger bag.

If I head into the woods, I will always carry a 35-liter backpack with minimal gear : water, stove, foam pad, small pouch of goodies, first-aid kit, gloves, a saw, a larger knife, food.

You could spend countless hours reading forums on the web and never be satisfied, always comparing your gear to other people's gear... it's not a perfect science. Just look at a typical day and see what could come in handy. If you head into the wilderness, bring what you think could make it relatively comfortable for a day or two in case something goes wrong (a bad injury, getting lost, etc.)