The aim of Stackexchange of trying to deliver good answers to grammar questions is excellent, but nevertheless Stackexchange has still a lot to do. I have just read the post "Why is present perfect used in this sentence?" and given a comment. Then I looked at the posts with the tag "present perfect simple". About 450 posts. Impossible to find a post where an exemplary answer is given to the question "When to use present perfect simple (Pf)?".
I see this as a problem and this may be the cause why the search function for tags is little used. How could one solve this problem? Should posts with exemplary answers have a special colour and be placed at the beginning of the endless row of posts?