Another user has made an important point about an answer I gave, rather than editing the answer directly. What is the appropriate way to give credit to that user when I edit my answer?
In general, it really depends on the nature of the edit that would have been needed. If it was a substancial edit that changes the nature of the answer, its probably polite to comment rather than edit - which is why you might have gotten a comment. I personally thank the user, credit him, and edit in the necessary information. The commenter may have been courtious, and its nice to repay that in kind. If its someone I know (for example in chat), and/or the person has low rep, or is working towards an edit badge, I tend to suggest they do the edit (with encouraging words!), and that I'd approve it once they did. Once again, its not a hard and fast rule, but rather a way to be nice.