Question: **I'm pretty sure this happens to someone out there now and then:**

You've read a question, done the work with writing a pretty decent answer, at least you think you have, then you find some detail in the question, either edited in at a later time or maybe not clearly defined in the title or pointed out in the context in the first place, that makes your answer either get down-voted because it isn't the most accurate or relevant answer or just kinda misplaced because it answers what you *thought* was asked, but then again, meh...

So, it isn't directly wrong, but neither a good answer for the question when you realize that you misread the whole thing. Could be that something got lost in internal translation (like inside your head, for non-native English speaking folks) or just poorly written. Could be you rushed for a bounty, at 4 a.m after a couple of beers, whatever.

What is the best approach in such cases?
Should I (or could I) delete my answer? What are the rules for if / when I can delete an answer?
Come to think of it, I really don't know the rules for if / when I can delete my own questions either... Is this written somewhere?

Does deleting an answer impact anything other than what it sounds like, e.g. the answer is Poof! gone or does it cause any other reactions / rep changes?
Is it considered bad practice to do so, if at all possible?

Answer: 
It can respond to another answer, but you still need to give at least a partial answer to the question.

Thus, answering like this is okay:

> 
> My experience about @X's answer (link) is negative, although I used a newer version of (...). Instead, what I did is (explanation), and now it works.
> 
> 
> 

[(example)](https://stackoverflow.com/a/39034132/1783163)

This answer is not okay, because it is a comment:

> 
> @X's answer does not work.
> 
> 
> 

The important thing is that the main focus of the answer should be at least a partial answer to the question on the top.

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Users starting with

> 
> It is not an answer, but...
> 
> 
> 

have typically two options:

1. Yes, it is an (at least partial) answer. These users typically think that giving a step-by-step guide is a requirement; the requirement is that at least a part of the question on the top should be answered. Users can get the supportive comment and editing out the "not an answer" part (superficial future reviewers might flag it for deletion without enough thinking on the details).
2. It is really not an answer. Some personalised advice, particularly in the case of newbies is still helpful, anyways flag as NAA (or for mod comment conversion if it is worthwhile).

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Who decides: mostly, the reviewers. I would say that about 80% of the cases are obvious (in the VLQ queue). For the border cases, this is why it requires 2k (or 1k on beta) the VLQ queue.

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Posting answer in comments: I do this if I am not sure or if I would flag my answer as VLQ/NAA. Because comments are second-grade citizens, if I write a bad comment, it will be at most deleted. I think the reason of others is the same.

If you are the OP, and one or more comment has actually the worth of an answer, then you could ask the commenter(s) to do it for an upvote and accept. If they remain inactive, you can summarize them in a self-answer ([example1](https://android.stackexchange.com/a/231985/50837), [example2](https://meta.stackexchange.com/a/296950/259412)). This is not forbidden, although you should mention your source(s) to avoid plagiarism.
There has recently been a discussion on Stack Overflow: [Is an answer that only addresses other answers not an answer?](https://meta.stackoverflow.com/q/403026/13552470)

The consensus of [the most upvoted answer](https://meta.stackoverflow.com/a/403027/13552470) is:

> 
> "Not an Answer" is the wrong flag in any case. "Not an answer" is for things like "I have the same problem, any solution?"
> 
> 
> If you're casting a moderator flag, the implication is that you want a moderator to take action on this particular answer, rather than leaving it to the community. The only reasonable response that a moderator can take to a "not an answer" flag is to delete the answer.
> 
> 
> So the question you have to ask yourself is, "does this answer harm the site enough that it must be forcibly removed by a moderator?" I would argue that it doesn't.
> 
> 
>