I think forums should generally let new discussions happen even on repeated topics. When you lock threads just because "we already talked about this," you kill the community vibe.
Tech and crypto change so fast - last year's Bitcoin discussion is already outdated. Plus, new members bring fresh perspectives that would be lost if we always redirected to old threads.
Instead of shutting conversations down, maybe just link to previous discussions while letting the new one continue. This gives context without stifling engagement.
The best forums feel alive with conversation. A bit of topic overlap is worth it if it keeps people talking and sharing ideas. After all, forums are about community, not just being a perfect archive.
What I notice about duplicate threads, especially the ones created around the same time and with generic subjects, is that there are usually no new discussions being raised in the newest threads, just a series of spam posts covering two or more pages. Some kinds of "vibes" will actually reduce the forum's cleanliness.
Once, there were lots of threads about how to stop crime on the Politics and Society board. Why do we really need duplicate threads on such a topic when everyone knows crime cannot be stopped? At that point, it was very necessary to lock further duplicate threads like that.
I am of the opinion that posts that appear as I have described above should be locked. But before they are locked, the link to the earliest post should be shared so that those who may find the topic interesting can continue the discussion there.