I carry a powerbank and various USB C adapters so if someone’s device dies I can help them out. It is a lot cheaper and smaller than carrying around seven different cables.
On top of that I carry Tylenol and bandages.
I used to carry a full first aid bag but kept forgetting to restock on supplies.
My cousin’s house, a co-worker’s desk, and my own shed, to name three different instances of lost or forgotten keys.
Also the stack of Masterlocks my friend thinks is funny to hide around my house but that’s a different story.