I've been reviewing some of my answers in an effort to improve them. During this process I ran across an answer that required a complete replacement. It was of poor quality and didn't belong here (yes, I'm embarrassed as well I should be) I deleted my original (0 vote) answer and replaced it with a new one. While it's clear that I can as described in How does deleting work? What can cause a post to be deleted, and what does that actually mean? What are the criteria for deletion? doing some further research on http://meta.stackexchange.com it appears that this practice may be frowned upon and may result in a ban So if I edit a post by removing all the text and starting over (in effect a complete rewrite) is that viewed differently than deleting and posting a new better answer and if so why?
Edit as much as you need to make the answer good enough. The only exception for me would be in cases where the OP has accepted your answer. That happened to me once where the OP had accepted the first version of my answer which was, in many respects, completely wrong. So I edited, fixed it and then left a comment to the OP letting them know that I did so and asking them to review and, if they so desire, remove the accept.
So, even in such a case, editing is the best thing to do, but just remember to let the OP know if you completely change an accepted answer. Apart from that, deleting and reposting isn't very useful since deleted posts are simply hidden, not actually removed, so you're just adding more data to the SE database for no good reason.
If you're re-writing an answer, you should do so literally. Deleting old answer and writing a new is not re-write.
- It's completely unnecessary to do so.
- It creates noise for 20k users.
- It could summon a ban upon you
- It creates confusion to see the history of the evolution of the answer
The only situation you should create another answer is when you have completely different answer to a question.