A Multitool
On a daily basis, I keep a full-sized multi-tool in my car, and another few in the house, and I find them extremely handy. When traveling, things will break, and having a little pair of pliers, scissors, or something to pry with will come in handy. Nowadays, most knife companies make a version of a tool that has no blade at all, so that you can take them right in your carry one. Otherwise, double-check the laws where you’re going and put a multitool in your checked bag, if you’re taking one so that you can solve all of those annoying little problems with screws and loose threads once you get where you’re going.