I mean, I've seen topics locked because they're old and people necro them. I'm sure we all have. But also we're told not to make similar topics than what has already been done before? So are those topics just off limits or what? I've always wondered about this.

</vague>

I've never noticed a problem like that; my perception is that making a thread similar to an old locked thread is accepted, as long as the old thread was locked due to necromancy rather than due to becoming a shitstorm.

The only thing I know about is:

If a irrelevant necropost happens on a solved thread, it gets (or got, look into some and find past examples) locked. It could be circumstantial, but if it was unlocked to begin with, and is still on topic, it shouldn't be too big of a problem.

If the thread's topic gets derailed, an admin can say to get back on topic, unless it's to a point that the forum is no longer needed, because it's derailed. If said thread wants to be touched apon, I don't know if it can be unlocked. So, I'd suggest asking an admin in case it's the derailed topic that was why it got locked, or if the thread that was no longer needed, before starting a new thread about an old topic.

So: I'd think it's usually safe to either make new threads, and include points from an old thread should it still bring questions or have points needed to be stated; if a thread gets derailed or is negative to begin with, the admins can find it smart to lock it, dependent on how far it went. I don't remember any forum-related "negative records" rules, so apply the commenting ones here: don't say stuff that'll get you records..."

Adding something worthwhile to an old thread is always welcome, just bumbing the thread to post nonsense or irrelevant information isn't. And the duplicate thread thing is only for when people try to make multiple threads on something where the older thread isn't yet 6 months old.

Ah, okay. That makes sense. I've just always been curious lol