The inventory of stickler proscriptions about English grammar and usage is bewilderingly extensive. Some of them (no prepositions at the end of sentences, none always a singular) have been repeatedly exposed as being without foundation; some (singular they, who overtaking whom) represent transitional stages; some are mere crotchets (the hopefully fetish).
And yet they survive, and any responsible writer and editor must judge how to deal with them. Ever eager to be of assistance, I offer these suggestions.
Sort out the genuine from the bogus.
You need to have a foundation for your judgments. Garner's Modern American Usage has a prescriptivist approach, though one informed about superstitions and shibboleths. Merriam-Webster's Dictionary of English Usage, tends to be more descriptive, with emphasis on historical developments, but its advice frequently coincides with Garner's. Know why you do what you do. You owe it to the writer and to the reader to know why you have made a judgment, and "This is what they taught me in sixth grade/journalism school/my first paper" won't cut it.
Obey the "rule," whether it is valid or not.
This, the coward's way out, will spare you insulting gibes from the pedants in your audience. It will also tend to produce stilted diction and syntax that will sound alien and off-putting to many readers.
Ignore the bogus rules.
This will result in insulting gibes from the pedants in your audience. So consider how many of them there are in your audience and whether their noisiness is in proportion to their numbers. Savor the inner satisfaction generated by a refusal to cater to ignorance.
Pay attention to register.
What is appropriate for subject, author, occasion, publication, and audience? If the article is meant to be conversational in tone, a singular they is increasingly apt to pass without notice. If the article is of more formal tone, you had better be sure that you have who and whom sorted out. Unless you are quoting speech or seeking comic effect, you can probably dispense with irregardless altogether.