When is it better to self-answer and when is it better to include detail in the question?
When you have an answer you should put it in as an answer, so that voting will rank it relative to other answers. Self-answering can help the site accumulate a good collection of questions and answers.
More detail that is needed to help solve the problem is always helpful, but if it does solve the problem, then the detail should be an answer.
If I ask here, it means that I haven't had any luck finding an answer myself.
Adding more detail to the question is when you now have more information to give to help people find an answer.
Answering your own question is when you find a solution yourself (maybe all the answers are wrong, but let you find the correct terms to google). If an answer is nearly right, I'll comment on it to let the user add that last bit, then accept it.
These are two completely different situations with nearly no overlap.
I never been the type to post a question only to answer it myself. Even though this is encouraged, I feel that if i was to do this then it was never really a question from the beginning if I already had the answer.
I have only been in a few cases where I answered my own question. This is when I ask a question and receive answers that might be on the right track; but not correct was a case when I came to answer my own question. Reason was to give the accurate answer to my question for others who could come looking for answers after finding my question. When I have done that though I would comment on the posted answer that put me in the best position to answer my question and give reason why their answer was not accurate.
I think that if you have an idea which you think might work, but you aren't sure, posting it as an answer rather than a question will:
- Allow you to modify it as an answer to an appropriate solution if it only needs a minor correction or is already correct
- Separate comments on your question from comments on your solution
- Keep the basic question lighter, and gets ranked along with other community answers
Unfortunately, it has the disadvantage that people who help you may not be rewarded, because they commented on your answer rather than providing their own. Also, people tend to be harsher with downvoting self answers, but I think they will be less critical if you list what you think are limitations.