Commas. Oh, commas. I feel confident saying that commas are the hardest and most complicated of the grammatical constructions in the English language (and most others you could name). This has led to a theory (frequently taught to children to keep them from having to learn in school) that commas are largely optional. You can use them here, you can use them there, you can just do whatever with them, and when you see them in a sentence they can be safely ignored unless you’re reading it out loud and need to know when to pause. That is to say, commas are largely for playwrights.
This is wrong.
However, it is also illuminative. The English system of comma usage is complex enough that most simply do not learn it. Indeed, I know more than one editor and many a writer who has declined to learn it, instead simply getting the very basics and hoping for the best. I, myself, frequently omit traditionally correct commas in my writing, particularly in something like reviews that need a certain tone and cadence more than they need grammatical perfection.
Therein we find the key. Commas can and often do gum up the proverbial works. They change the way something sounds, and not always for the better. Omitting them is frequently a good choice in non-technical writing, and while I do have a few sticking points (oh, hello Oxford comma, I didn’t see you there) language must always be in service to meaning, not the other way around. If punctuation, capital letters, and paragraph breaks become a problem, omit them. Of course, you want to be really, really sure that’s necessary, because people will judge you when they fail to get the meaning of your 10,000-word stream of consciousness (the plebs).
When you want your writing to ring a certain way in the mind, commas can be used to simply denote a pause in reading, a half-beat breath to create dramatic tension, mix up paragraph cadence, imitate a speech pattern, or otherwise creatively alter the way a certain sentence is read. They can be removed to have something read like it’s being blurted out, to speed up the pace of a sentence such that it reads breathlessly, or even to give the impression of a clueless narrator. In all of these cases, commas are stylistic rather than grammatical. They are not used correctly, but they are nonetheless used in a valuable way that should not be underestimated in its importance.
When you hire an editor, you must be certain that they know you are using commas stylistically. Indeed, all stylistic choices should be covered. An editor should ask you these questions – some of the more anal retentive may even create a style sheet just for your piece. If they don’t, though, maybe be a little wary. If you love them enough to overlook it, tell them exactly what they need to know before they start, not when you get the edits back. You shouldn’t be going through rejecting one change after another, they should be catering to your style.