How much should you refine a question before opening a new question? When editing your own question, sometimes the initial problem is something completely different to what you expected, and the original question becomes obsolete. How far do you think you should edit and refine a question before simply opening a new one? Recent example: * < * Why does RAID5 with an odd number of data disks have poor write performance

My opinion (as stated in the comments on the RAID-specific question you cite) is that if the existing comments and/or answers (if any) on your question would no longer make sense in the context of the modified question, then you should open a new question. Of course, if your old question has no continuing value, then you should also close your old one (if possible) to keep things tidy.