Writing so much eventually leads to situations where I'm no longer sure if have already written about some topics. There might be multiple reasons for that: I might have forgotten that I wrote about it. I might have thought about it earlier, written the topic down and then forgotten I did that. Then after a while I remember it, write about it, but don't remember to remove it from my to-be-written -list.
It's hard to keep track on all the things I have written so far. There are so many. No point reading through them all just to make sure I don't write duplicates. If it happens, it happens. And it just shows how important the topic is. It's not just something that comes and goes, but returns every now and then. Maybe it's worth writing more than once in that case.
And I'm sure even if I write about the same exact topic, the result wouldn't be exactly the same each time. There is always some time in between and I might have learned something new about the topic in the mean while. Or my mind might just have changed since the last time. There is always room for new perspectives.