Recently we have the case, that a very specific question was asked that falls into the scope of a more generic question about the same thing. This should however just be an illustration, the issue is a general one. I really only want to address questions, that are narrower in scope but ask clearly the same as the more general question. If the narrower question asks about something slightly different but related, it shouldn't be closed at all.
There are several options I see currently:
Answer or edit an answer to the more general question such that it addresses the more specific question. Then close the specific question as a duplicate.
The advantage of this approach: All information is concentrated in one place. Possible disadvantage: One aspect of the specific question might not be exactly addresses by the more general answer (however that should not be the case, if this answer is specifically written/edited after the specific question arose).
Leave the more specific question open and write an answer. Use relevant paragraphs from answers to the more general question by citing them. Thus there is no unnecessary repetition and the specific question gets an answer that is tailored to its very own issue. However like this the more general question does not get "better" by introducing this new aspect.
What do you think should our approach be - one of the above or something entirely different?