You finish a draft, reread it, and it looks fine — every sentence triggers the meaning you meant.
But that's the trap: rereading, you recognise your own words instead of judging whether they'd land for someone who wasn't in your head.
William edits nonfiction for a living, and the same seven problems surface every time — always about the reader, grammar dead last.
So what does an editor catch that you can't?
That your draft was built for you, not your reader.
An editor checks what you're too close to see: who the reader actually is, whether your point sits where they'll look for it, whether you've framed a problem they have, whether you keep calling your key ideas by the same name, whether characters sit in the subjects and the logic is named — and only then, the mechanics.
Fixing the reader-facing problems first is what finally makes the polish worth doing.