[bjourne]

Good rules of thumbs are given in the "Deciding which to use" section of the article. For the fetch() function, I'd keep most parameters as is since they don't change the essense of the function. But "cache" and "redirect" do (following redirects can cause N http requests rather than just one and using the cache perhaps 0) so I'd refactor them as new functions. Imagine adding retry functionality to the fetch() function using parameters. I think you can see how this leads to feature creep.