Among the many different kinds of evidence that might be used to support an answer on this site (passages from a story, quotes from an author, citations to published analyses, close reading, well-reasoned arguments, etc.) is personal experience. This probably works especially well with questions that aren't text-related, e.g. about care of physical books, publishing practices, etc.
Of course, answers based on personal experience should be more than welcome. My question is: what kind of support is required to make such an answer a good one? By "good" I don't mean "non-delete-worthy" - we've already had that discussion and there doesn't seem to be consensus in favour of deleting insufficiently supported answers - I more mean "upvote-worthy". As we know, good answers should be justified and supported; I for one try to downvote answers which aren't explained or backed up properly. I'd thought that personal experience could be backup enough in itself, but then we get examples like this question where there are two different answers, both apparently based on personal experience, with two opposite conclusions:
In my experience, having worked in-house in the publishing industry for more than 10 years, it is quite usual for the cover to be decided by anyone other than the author. It's usually done through consultations in long meetings between the publisher, production and marketing who have commissioned designers to make about a zillion options.
I've worked in the publishing industry for over 15 years, and in my experience, authors have a lot of control over the covers of their books. The publisher would find a suitable illustrator, and then we would set up a meeting between the author and the illustrator where they discussed their ideas for the cover. The author didn't have final say over the cover, but they were involved.
When there was just one answer, I upvoted it because "yay, nice experience-based answer". Now I'm not sure how to vote. Is one of these answers wrong? Are they both correct but coming from different contexts? Thus, I'm wondering if something else is required to make an experience-based answer 'credible', or if in cases like this we should just treat both as good answers.