But now I was wondering whether I made the right choice. So, when do we actually have to choose "Recommend Deletion"?
Recommend deletion if the post should be deleted under PPCG or Stack Exchange rules; otherwise say "Looks OK"; never edit it
This includes situations where:
- An answer intentionally breaks the rules, or accidentally breaks the rules and was not fixed within a reasonable length of time of the problem being pointed out
- An answer is not of the form expected as an answer to the question (e.g. a code-golf post is answered with a complaint about the specification); note that in this case, you'll probably want to pick a canned reason from the list of recommended deletion reasons, e.g. "this should be a comment"
- A post obviously contains subject matter that's explicitly offtopic for the site (such as a [tag:code-trolling] question); note that in borderline cases, voting to close is OK, but voting to delete is something that needs more care
- A question is completely unsalveageable and will clearly never be edited into a viable challenge (or non-challenge post)
Note that if the post is so bad that it would be instantly deleteable on any Stack Exchange site (i.e. it's spam in the sense of "advertising an external site without disclosing your affiliation", or offensive/rude/keyboard mashing), you should place a "red flag" on the post (flag → "spam" or "rude/abusive" respectively), in addition to recommending deletion. There's more than one sort of deletion available, and it's important to make sure that the post is correctly characterised as being in moderately good faith or as being outright abusive.
In any situation where the post doesn't fit into the above categories of things that should be deleted, say "Looks OK" to clear it from the queue. The Low Quality Posts queue is really buggy and you want to move posts out of it as quickly as possible. (Note that there's an autoflagging bot in the Stack Exchange software which casts a lot of dubious "low quality (auto)" flags, which feed into the Low Quality Posts queue.) In particular, never edit a post from the queue, no matter how much editing would improve it, as this triggers one of the worst bugs on Stack Exchange; instead, wait for the review to be completed, and then you can edit the post safely.