At some point, everyone learns how to write. Just like learning math, it has to happen, and some people despise it. Some people love it. Some people decide they never want a career that touches writing, while others may decide they want their career to be nothing but writing.
All that aside, everyone should do it. Writing is good for the soul in a way that talking isn't. It helps to organize thoughts and make them permanent by putting them somewhere permanent.
Growing up, I always dreamt of having a diary that historians may one day find and use to piece together my time. (A ridiculous thought, I know, but I was a 7-year-old.) That never happened. I'm too scatterbrained for something so permanent; I ended up writing my thoughts anywhere I could.
Tests, homework, etched into my desk, penned on my arm, written on scratch paper, doodled in bubbly letters on my class notes—if I could write my thoughts on something, I did. Because of that, I have an odd time capsule: all of my old stuff.
Some of the writings are bland, like my list of things that I had to do. Others are a bit more emotional, like me ranting about something awful (or that I thought was awful).
It was how I coped with everything, even the good things. I have always felt my emotions too strongly, so getting them out was the best way to keep myself from exploding.
For the person who has trouble feeling emotion, it could help organize thoughts to make it easier to understand what they are.
For the person who has no issue with how they feel, it could simply be nice to have permanency to an idea or an emotion.
There's a purpose to writing for everyone, even if you don't like it. Have a lot to do? Write a to-do list. Have a lot on your mind? Write it all down. Need to vent? Paper never judges.
There is no bad time to write.
If you can't physically write, do it in your head. Think about what you'd be writing if you could. Imagine yourself actually writing it down. Surprisingly, that's helped me remember things better.
There isn't a downside to it (barring any physical limitations like a disability). Sure, it takes some time out of your day, but everything does. Going to the bathroom takes time—so take your writing with you! Waiting for an appointment or a meeting? You have time to write!
Take some time out of your day and write. Your sanity and productivity will thank you.