Ok, I am cutting back. I am putting a ITP A3 Titanium with ONE tool in my left pocket. My Truck key ring has keys, a spyderco bug, and a photon light. That’s in the right front with a bigger knife that I swap out every day. What is the one tool you must have/provides you with the most functionality? Currently I swap out a swiss-tech micro-max and a victorinox midnight manager to go with the light. What do you suggest? Remember, just one, because two becomes 3 which becomes 5 which becomes a bag……………….