Writing is a trade, and a skilled one. Like in any job, some days are more productive than others. Some days you write a (if I may say so myself) a witty nostalgia piece about your summers at camp, and some days you start a blog posts with a subpar introduction.
And, like any job, there are tools that make it possible and tools that make it more efficient. Of course there’s the standard pen and paper, which, if I am carrying any type of bag, you are unlikely to find me without. There’s the last measure of any number of applications that one can use to type on a phone, though that tends to be a cramped and limiting experience. Never forget the older technologies, like typewriters.
Then there’s my personal favorite, typing, especially on a laptop. There’s something about the sound of typing on a keyboard that makes me feel productive, especially if I actually am being productive. I like the fact that as I think, I can see my thoughts take shape as letters, sentences, and paragraphs.
No matter what, how many, or what type of tool you use, if you want to be a writer, always carry some kind of tool for your trade with you. You never know when the muse will rain down inspiration upon you, so make like a Girl Scout and be prepared.