One of the best sentences in Strunk and White’s popular writing guide, The Elements of Style, is this: "A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts."

I would go further: a sentence should contain no unnecessary commas for the same reason that a symphony should have no unnecessary pauses. True, commas add rhythm, and more importantly clarity, to our writing. But, if we use too many, of them, our writing becomes difficult, for people, to read, and our ideas end up fragmented, instead of connected.

For years participants in my grammar and writing workshops have magnanimously imparted their golden rule for commas: use a comma whenever you would take a breath. And for years I have regretfully but pointedly burst their bubble. That simple rule, which so many have clung to since their tender years, works occasionally (even often, if you’re a speechwriter or playwright), but it also gives rise to the superfluous commas that pollute our prose, bobbing up disconcertingly like plastic bottles in the ocean.

While comma use is sometimes a matter of personal taste, there are certain places where this mark does not belong.

Grammatical bonds

What grammar hath joined together, let no comma put asunder. Don’t let a comma split the grammatical bond between a subject and its verb, a verb and its object (or its subject complement, if it’s a linking verb like to be) or a preposition and its object, even if you think a pause is in order.

• NO All duly registered members of this exclusive English equestrian club, are permitted unlimited access to the club’s stables and pubs. (splitting subject and verb)
• NO The mugger was stunned to find that the elegant businessman had in his pockets, only three dollars and half a liverwurst sandwich. (splitting verb and object)
• NO The only thing the lottery winners wanted was, to live their lives as they had before becoming millionaires. (splitting verb and subject complement)
• NO We mailed illustrated concert programs to, every symphony subscriber and every music store in town. (splitting preposition and object)

Note that it is perfectly acceptable to interrupt these grammatical unions with a parenthetical element and a pair of commas.

• YES The mugger was stunned to find that the elegant businessman had in his pockets, besides a soiled handkerchief, only three dollars and half a liverwurst sandwich.

Coordinating conjunctions

As explained in "Commas That Count," the coordinator is a comma that precedes a coordinating conjunction (for, and, nor, but, or, yet, so) that is joining two independent clauses. Be sure to put the comma before the conjunction, not after it.

• NO The Green Party backbencher asked her question three times, but, the cabinet minister still refused to answer directly. (remove comma after but)

When the elements joined by a coordinating conjunction are something other than independent clauses, it’s best to dispense with the comma (though see "Bending the rules" at the end of this article).

• NO After Tiffany got Leonardo DiCaprio’s autograph, but before she could look at it, she fainted cold at the star’s feet. (conjunction joins two dependent clauses)
• NO Fluffy white cumulus clouds, and clear autumn air made it a perfect day to stay inside and watch TV. (conjunction joins two phrases)

Restrictive elements

A restrictive element is the opposite of a parenthetical element. It is a word or group of words, usually descriptive, that is necessary to the sentence because it defines or limits (restricts) the word it describes. Do not use commas with restrictive elements.

• NO The soup tureen, from the antique shop, was actually less expensive than the one I saw at the neighbourhood flea market. (element is restrictive, not parenthetical)

To test whether an element is restrictive, try omitting it from the sentence. If the sentence’s main message is no longer clear, the element is restrictive. If the main message is fine, the element is parenthetical.

• NO Bob Dylan wrote the ballad, "The Wedding Song," in 1974. (can’t omit the element; it is restrictive)
• YES  Bob Dylan’s first wife, Sara, left him soon after he wrote "The Wedding Song" for her. (can omit the element; it is parenthetical)

Series

Commas between items in a series stand for the word and. Do not place a comma before the first item or after the last, since you can’t use and in either spot.

• NO The developers received passionate pleas and lengthy petitions from, store owners, local residents, and area building managers. (remove first comma)
• NO The children waved flags, beat on toy drums, and blew noisemakers, as the parade passed by. (remove last comma)

Remember that the comma before and in a series is optional.

And with a series of modifiers? Therein lies a bewildering comma conundrum: sometimes you need commas; sometimes you don’t. The decision depends on whether the modifiers are coordinate or cumulative.

Coordinate modifiers all independently modify the same word. You can rearrange their order and insert the word and between them. A series of coordinate modifiers requires commas.

• YES She is a careful, conscientious, knowledgeable editor.
• YES The caterers prepared an array of rich, colourful, tasty sweets for the buffet.

Cumulative modifiers do not separately and equally modify the word they appear with. Instead, they build or lean upon one another. You cannot change their order or insert and between them. A series of cumulative modifiers takes no commas.

• YES She is a bilingual copy editor.
• YES The caterers prepared a vegetarian bean soup for the buffet.

To complicate matters, a series may include both coordinate and cumulative modifiers. But if you apply the dual test of rearranging and inserting and, you should get the commas right.

• YES She is a skilled bilingual copy editor. (one coordinate modifier)
• YES She is an underpaid, skilled bilingual copy editor. (two coordinate modifiers)

Bending the rules

Punctuation is like any art: once you have mastered the principles, you can bend them. It’s fine to depart from the comma rules from time to time—if you have a good reason.

George Bernard Shaw once said, "The golden rule is that there are no golden rules." That’s pretty much what I tell my workshop participants as I strip away their lifelong illusions about commas and breathing. Instead of one golden rule, we have many plastic ones—but that’s far more practical, especially if we plan to break one now and again.

Test yourself