Editors need continuing education. It's true that if you are merely a hack, you can get by with something you remember your teacher telling you in freshman English, some arbitrary dictum your first editor insisted on, some rule in that ten-year-old copy of the AP Stylebook that is the most recent edition you've bothered to acquire. But if you want to be more than a hack, you must keep up. Not only is the language changing, but our understanding of the language is changing. Garner's fourth does not say quite the same things as Garner's first.