There’s a tendency to only start writing about a topic once you feel a level of mastery over it, and I think this hurts the process of learning. The “Toolsday” podcast mentions this, how it’s easy to forget what the actual hurdles of starting up a new project were and instead focus on, as someone more distant from the learning process now, what you imagine the hurdles would be for new people.
Similarly, in his book Pragmatic Thinking and Learning, Andy Hunt talks about how Experts in a topic are often much worse at teaching than people who are experienced beginners or newly proficient in that topic because they rely much more heavily on intuition (intuition which relies on having context) than standardized rulesets that can stand on their own. Being able to write from a context-less perspective, something that’s much easier for newbies (as they are relatively context-less).
So write about an idea while it’s still fresh. You can always edit for clarity and simplicity, but it’s much harder to capture the sharp, poky bits of a topic when you’ve learned to intuitively account for them, and your audience, which is presumably using your post or article to learn something they’re still novices at, will need to know about those sharp, poky bits to be able to stay enthusiastic and feel like they’re not insane for encountering them and having trouble with them.