Separating dependent clauses and introductory phrases with commas in compound and complex-compound sentences

Question

I know that you are supposed to separate dependent clauses and introductory phrases with a comma if they start the sentence. Examples:

1. If you are ill, you ought to see a doctor. (dependent clause)

2. After the adjustment for inflation, real wages have decreased while corporate profits have grown. (introductory phrase)

Reference: https://owl.english.purdue.edu/owl/resource/607/02/

However, the above reference does not give examples of punctuating compound and complex-compound sentences that include dependent clauses and introductory phrases in the second part of the sentence.

Example of such a sentence with original punctuation kept (I took it from Wiktionary — an example of usage for word particular in sixth definition):

He is very particular about his food and if it isn't cooked to perfection he will send it back.

I think that there should be a comma after the word food, but that is not my question.

My question is if there should be a comma after the word perfection.

Similarly, sould there be a comma after an introductory phrase which comes after the first indepedent clause but before the second indepedent clause? (Although it is probably considered to be a part of that second independent clause.)

[independent clause], + coordinating conjunction + [introductiory phrase] + [independent clause].

Comma or no comma after an introductory phrase in the above structure?

Answer 1

Punctuation is a matter of style, and as such you should be governed by your manual of style, either the one you've chosen or the one thrust upon you. I prefer The Chicago Manual of Style, but whichever one you choose realize that the there will always be allowance for the author's necessarily subjective judgment.

CMS notes that when it comes to punctuation, form follows function, and that said function has three components: to clarify meaning, to aid the reader, and to contribute to style. There are two schools of thought -- close punctuation (which supplies the marks to follow the syntax as much as possible) an open punctuation (which supplies the marks only in those cases of possible "misreading.")

Close style will always recommend and open style will usually concur that coordinated independent clauses be separated by a comma unless the the clauses are very short:

George washed and Martha dried.

In the given example, a middle-of-the-road style will thus recommend that the sentence have a comma preceding and and following the dependent clause:

He is very particular about his food, and if it isn't cooked to perfection, he will send it back.

Close style will bracket the dependent clause with commas:

He is very particular about his food, and, if it isn't cooked to perfection, he will send it back.

This looks choppy, and even in 1982 when the 13th edition of the CMS was recopyrighted, this style is noted as somewhat out of favor.

A strong open style will omit the commas in the second clause or even omit all the commas on the grounds that a markless sentence won't lead readers into misparsings.