What's the ONE thing you must take with you on every trip?
(Can't believe this hasn't been a topic here before, but I didn't turn up anything with a search)
I know a lot of you folks are one-bag travelers, so you know that every ounce counts. I'm sure you all have something you can't leave home without - whether it's your favorite bag, headphones, jacket or even a power strip. It's the one thing that you MUST take with you whenever you travel, and you're never able to find a local equivalent that's just as good.
What is it & why?