So the official SE policy as clarified by staff is that it's only questions that make duplicates, not answers. The core philosophy is:
[1] Stack Overflow is not meant to be a library of reference manuals. It’s supposed to contain the same information as a library of reference manuals, in the form of millions of questions and answers. Combined with Google, that gives us the magical power of a library of reference manuals you never have to read! It’s like, you got to the library, and there’s a wizard there at the door, and you ask your question, and, instead of being told to read a book, you just got (are you sitting down?) the actual answer!
[2] It's far more common to have many subtle variations of a question. I think that's OK, because that's how the world works. Trying to shoehorn a bunch of semi-related things into one arbitrary container in service of some Highlander-ish "there can be only one" rule is ultimately harmful.
Ultimately we're a Q&A site whose success comes from giving the smoothest and highest quality experience to people looking for the answer to a question.
If someone asks or googles "Why did X happen to character A", and they get a confusing link to "Why did character B stop doing Y", that's not the smooth experience SE is intended to give. Maybe they'll figure out on their own that paragraph 3 of the second answer goes on to talk about character A and X. Or maybe they'll just think "This site gave me a broken link".
And perhaps more importantly, we don't want to choke out the possibility of some other person writing a really great, exceptional, detailed answer to "Why did X happen to character A", that maybe makes the same basic point as paragraph #3 of answer #2 under "Why did character B stop doing Y", but adds high quality analysis, quotes and/or sources specific to X and character A. For example, this great answer by a linguist on the meaning of the accents in Game Of Thrones couldn't have been written if the attempt to close it as a dupe of a question about Game of Thrones characters mostly having white skin had been successful. The earlier question does have an answer that mentions that the source books were inspired by the English War of the Roses, which is also part of the newer question's answer, but both excellent answers add much more different, question-specific, high-quality detail around this one shared fact.
So the best thing is, if the questions are different but you can't think of much to add beyond what the other question's answer says:
- Write the detailed answer in whichever question it fits best
- Write a quick summary with a link and a quote in the other question. Something like:
X happened to character A, because character B stopped doing Y. [elaborate if necessary]
I wrote about this in more detail under "Why did character B stopped doing Y", this is the most relevant point:
[Most relevant quote here] lorem ipsum lorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsumlorem ipsum]
It takes seconds, and it minimises duplication while also quickly and smoothly giving everyone the answer they're looking for.
And perhaps more importantly, it doesn't snuff out the possibility that one of our many ridiculously knowledgeable users could come along and enhance the newer question with one of those excellent answers full of extremely specific details you never even thought of!
This is Stack Exchange. Someone can do better than that one relevant sentence in one paragraph in one answer under a different question!
