Has anyone heard of good resources that teach you "when to use X" instead of "why you should use X"?

It's somewhat understandable that the official websites of frameworks/tools/libraries/languages/services tend towards espousing the advantages of the thing and leaving out most of the drawbacks. That's just how the incentives are aligned. But even the average blog article about a tool posted on HN rarely talks about what situations it is most effective, and what situations it should potentially be avoided. I suppose it's a natural consequence of blog authors only knowing so many tools, no single person knows them all.

I'm not saying this information isn't out there – just that it seems like the exception rather than the rule.