...in my first ten years of editing.
Editing is only objective to an extent
Voice matters as much or more than rules
Standardize style guides are good; personalized are better
MS Word has so. many. shortcuts
"No" is a good thing, for all parties
You don't have to do everything
If someone is stuck, it's not because they're broken (myself included)
Some books take longer than others
Some authors (and editors, and humans) take longer than others
Books are a process, not a product
What I have learned, over and over again, every year since:
None of that matters if the vision for the book is still fuzzy (either in your head or on the page)
Checking (and re-checking) your intentions for the book at each new stage of the writing process makes it much easier to align our work to those objectives—your objectives.