If I have a question to which the answers lead to realizations that dramatically change the scope or context of the question; should I edit the question to rephrase or expand it; or should I ask a new question in reference to the old one, incorporating references to the answers and original question?
Edit: Or, as an alternative, answer my own question.
You should always post a new question if you have a new question - otherwise the existing answers are tangential at best and nonsense at worst.
If you're giving up on the question because you realized it was a bad question, just delete it.
If you're giving up on the question because you found the answer and it led to a new question, answer it if you think the answer might be useful to someone else. I would err on the side of deleting rather than answering your own question - if the answers would be useful to someone else, someone else will probably ask it again, and you'll know more to answer it when they do.
