Do’s And Don’ts :



One unusual use of apostrophes is to mark plurals of words when they are being treated as words, as in “pro’s and con’s,” although plain old “pros and cons” without apostrophes is fine.


But “don’t” already has one apostrophe in it, and adding another looks awkward in the phrase “do’s and don’t’s,” so people wind up being inconsistent and writing “do’s and don’ts.”


This makes no logical sense. You can also skip the extra apostrophes and write “dos and don’ts,” unless you’re afraid that “dos” will remind your readers of MS-DOS (but that unlamented operating system is fast becoming a distant memory).