Blink and you missed it, or so they say, those buggers who always seem to be saying something. Only, most annoying, they tend to be right. The thing with writing is that though there is plenty of time to write and hopefully you all have long lives, the moments are transitory. If you don't seize the moments as they occur, you miss them.
Writing is topical even when it manages to transcend the time period when it was written. To be a writer, you have to take advantage of the moments you have. You have to write.