Tool I use the most

Everyday, multiple times a day, I use my handy snap-blade utility box-cutter knife. It costs 2 dollars. It’s made of day-glo orange plastic. I use it like a pocket knife for opening and liberating all kinds of things, but it weighs almost nothing (no pocket wear), is easy to re-sharpen (snap off the end), instant to engage, and quick to put back. They are so cheap and featherweight I keep one in all my pants, coats, and bags. If I lose it I don’t care. I really miss having them when I travel by air (although I know from unintentional experience they are usually undetectable by the machines.) — KK