Both situations can happen. I think that ideally you write about a topic you've grappled with and know it well at that moment. I've done this a number of times

Both situations can happen. I think that ideally you write about a topic you've grappled with and know it well at that moment. I've done this a number of times and am really happy that people comment it's been useful. On the other hand I've also come across many low quality articles as well.