One little holdover I carry from my days in international economics is that I collect foreign money. To me, there's something fun about going through a collection of coins and notes from literally all over the world, and having them all in one convenient binder. In one place my Portuguese escudo will be next to my Italian lira and my Greek drachma, all under the watchful eye of my German marks and Spanish peseta. And of course, people often ask me about the real value of all this currency. My answer (at least in the cases mentioned above) is always the same: "Nothing." And yet, while it has no value as currency, to me it is worth a lot more.
Writing and the works we create have this same duality of existence. If you write a story about a particular adversity you've overcome, what is its value? Unless it won you a prize in a writing contest or convinced someone to give you a writing job, then probably nothing. However, never let that deter you, because writing such a story probably means the world to you personally, and that's a worth we need to recognize. It's also something we should feel ready to capitalize on in our own way.
Recently, I wrote a story about processing grief. That part alone has value to me, so if I had stopped there it still would've been a wise investment of my time, since the writing brought about some catharsis for me. However, I took it a step further. I decided to share the piece with a writing workshop to get some feedback on the shape and style, and any tips on how I could strengthen this ultimately fictitious story involving a very real process of managing grief. The advice poured in, the discussion was productive, and that could've been the end of it - mission accomplished. However, after the workshop, someone pulled me aside and thanked me for sharing this piece, as it helped them think about the grief in their life and how their coping mechanisms had been functioning. At that point, my piece of minimal value and infinite personal worth just paid off the best return possible.
I can't say every piece I write will change lives - the story about the first time I got super-drunk will, at best, turn people off of mixing Amaretto and beer (yes, I did that). However, I don't write for some big return in value. I write because the creation, the process, and the dividends of churning through my brain to create stories from mere keystrokes is worth more than even I can truly understand. And whenever you write something, think about what it is worth to you first and foremost. Its value to other people can't really be measured (like my old one-million Turkish lira note), so just write things that are worth something to you. Those will be priceless.