Next week would have been my best friend’s 37th birthday. She died of breast cancer almost six years ago, and tucked away in my nightstand is a note she wrote me during her cancer battle — one I still haven’t opened since she passed. I don’t reread it. I don’t even really touch it. And yet, just knowing it’s there gives me a surprising amount of peace.

That feeling stayed with me while listening to The Correspondent by Virginia Evans, a book that not-so-subtly reminds us of the power of the written word. Evans describes letters as “the pieces of a magnificent puzzle… the links of a long chain,” scattered across the world like “the fragile blown seeds of a dying dandelion.” Even if those links are never put back together, even if they’re never reread, isn’t there something kind of wonderful in that? The idea that a life, a love, a soul-changing friendship, is preserved somewhere in ink.

Which brings me to three reasons to write your best friend a letter — aside from the fact that life is fragile, time is weird, and anything can happen at any moment (sorry).

First, letters slow you down enough to tell the truth. You can’t casually skip over what matters most. Writing by hand forces a pause. It asks you to sit with what you really want to say instead of skimming the surface.

Second, letters endure. In a world of algorithms and iClouds, where memories are filtered, sorted, and, let’s be honest, one forgotten password away from disappearing, letters preserve something real. They live in drawers and boxes, aging alongside us, asking nothing but to be kept.

And finally, letters outlive the moment they’re written in. As Evans puts it, “this very letter may one day mean something, even if it is a very small thing, to someone.” Sometimes the comfort isn’t in reading the words at all; it’s simply in knowing they exist.

So write the letter. Send it, or keep it. You never know how, or when, it might matter... which is both comforting and mildly terrifying, depending on the day.