I recently added an answer to a question about chains falling off a single chainring on the front when there is no derailleur. The answer is here.
There has been lots of interesting content added in the comments to the answer, and even to another answer which further adds value.
My understanding is that we should be editing the question and answer to provide a more comprehensive single point of truth, rather than making people read multiple answers and comments to get a full picture.
For example, on another question I asked I realized that I was missing a crucial part which was causing my problem. Zenbike had added an excellent answer on troubleshooting, based on the assumption that I did have all the parts. Rather than add another answer, I edited his answer to include the indication that a part was missing, followed by the troubleshooting tips.
What should be the edit answer/add comment/add answer strategy?