(thanks to Pieter Geerkens for motivating this question)
I recently asked a question on History SE. In that question I did some prior research, and found a paper with what seemed like a close-to-complete answer.
But I still thought that the question was worth asking, because I didn't have the expertise to determine whether the paper I found was missing out on something important, whether it reflected the historical consensus, whether it didn't mean what I thought it meant, etc.
So I asked the question. Because of that one paper, I thought that I had done enough prior research. However, based on community discussions, I think I have come up with a guideline and I am wondering whether you agree with it:
When asking whether a particular source conclusively answers a particular question, I should almost always try to include multiple sources in the question.
The idea would be that this would a) demonstrate that the question is non-trivial if the two sources disagree, b) give people answering the question a starting point for tackling at least some of the issues in evaluating any sources that may be out there.
Tangentially related question: Is it okay to ask a question where you feel you "know" the answer, but fear what you DON'T know?