My wife pointed out that there shouldn’t be an apostrophy in ‘Do’s’ since it is not an abrieviation of ‘Do is’ but a plural of ‘Do’.
This makes sense, so why do English speaking people write Do’s?
To avoid confusion with the Spanish word for “two” or an obsolete PC operating system. Also, “do” is a verb therefore is it kind of non-standard to use a plural noun form of it, so the rules get dicey.
It is common to use an apostrophe for the plural of a word that otherwise might be confusing, especially in technical writing.
I’m a former book editor. Exactly what CookingWithGas said.
OK, Walloon & CookingWithGas, but please clarify: Am I wrong for getting my cute little panties in a bunch when I see 's used to pluralize (except as noted above, when there may be confusion)?
Thanks for the vote of concurrence, Walloon! I am not trained as an editor but I used to do a lot of technical writing and editing and studied a bunch of style guides along the way.
Matchka, aside the above examples, any time that an apostrophe followed by an “s” is used to make a plural is just plain wrong. How many times have I seen signs like
Whether or not that justifies getting your knickers in a knot is a nongrammatical question, however. 
An apostrophe should be used to make a plural only in dire straits. As CookingWithGas said, to prevent confusion: the plural of the word do can be written do’s to prevent it from being confused with the Spanish word for two, dos, or the computer operating system DOS.
For some reason, people on these boards keep referring to the plural of Nazi as Nazi’s.
In an english sentence, where Spanish numbers are not regularly inserted and in a non-technical environment - eg, most other people’s lives - why is it assumed that ‘Dos and Don’ts’ needs an extra apostrophy? No-one I know says DOS anymore, it was never really used by non-technical people and so I don’t believe this is the reason for Do’s (since Do’s have been around longer) and the Spanish I know don’t insert Spanish words in their English sentences (bar puta, it seems).
I’m asking about this sentence specifically.
Are we taught at school that Do’s is the correct plural for Do?
flapcats–Well, my remarks in my original answer about DOS and dos were intended to be somewhat humorous since it is unlikely that anyone could read “dos and don’ts” and possibly get them confused. (I’d be willing to bet, though, that has at one time been some PC industry magazine article out there entitled “DOS and Don’ts.”)
Nonetheless, “do” is a verb (and an auxiliary one at that) and it is just not normal to make a verb plural and use it as a noun. I don’t know if there is any convention at all for doing so.
Now I will retreat from my prescriptivist posture and become a descriptivist. English is not designed, it just evolves organically. So there is stuff in the language in common everyday use that doesn’t have any logical rationale. Using an apostrophe in this phrase is not a rule, it’s just the way it’s done. You can’t really synthesize a rule from that usage that would apply to any other situation. Some aspects of language are like etiquette–sometimes it makes sense but sometimes you just do it because that the way it’s always been done, so you don’t have to rethink it every time.
This is kind of an odd distinction, because however rare DOS (Disk OS) is, dos (plural of do) is probably just as rare, except in the phrase “dos and don’ts”, where ambiguity is not really an issue.
Well then, what would be the plural of the **noun **“do,” as in “hair do”?
A quick Google shows thousands of examples of both hair do’s and hair dos. Not to mention a few “hair do’s and don’ts”.
My point is that there is not a rule for everything.
Can I just weigh in with a vote for “dos and don’ts” with no apostrophe in “dos”.
That’s how we write it at the (British) newspaper I work for. No need for an apostrophe whatsoever. Likewise “hairdos”, “Cornettos”, “folios” and “potatoe”
Suppose you were writing a story about Bill Clinton and wanted to make a plural of “is.”
Clinton’s multiple ises?
Clinton’s multiple is’s?
Though technically wrong, the second seems preferable to me.
(Of course, most writers would simply rephrase it.)
Hmm . . .
Ises and isn’ts
Is’s and isn’ts.
I was taught that when a verb is being used for itself, and not for its meaning, it should be put in quotation marks.
"Do"s and "Don’t"s.
How goofy that looks.
Advisable and non-advisable practices.
Here’s another apostrphe conundrum I actually find myself writing.
Shade’s is used as an abbreviation of Shade’s house.
So what is the abbreviation of Shade’s is (or for that matter, the possessive)?
Shade’s’s?
Shade’s’?
Or is it a judgement call?
Since you don’t say Shade’s’s, you wouldn’t write it, either. You say Shade’s is, and so it should be written.