One of English’s favorite prefixes is “pre,” three little letters that mean “before.” It helps modify words like “nuptial,” “conception,” and “disposition,” among hundreds of others, to include a “pre-condition.” Even “prefix” has its own “pre” fix.

“Pre” has many legitimate uses: A “pre-existing” condition existed before something else, usually the issuance of an insurance policy. A nation makes a “pre-emptive” strike on another to prevent itself from being struck (though has anyone ever heard “emptive” used without “pre”?).

But sometimes the “pre” gets out of control. Used cars are now “pre-owned,” a term apparently invented by car salespeople. The funeral industry outdoes them, touting “pre-planning” for your funeral “pre-need,” for which you “pre-pay.” We even look to “pre-fix” computer problems by installing antivirus software. (Ignore the “pre-fix” meal that appears in hundreds of news stories, which isn’t a “pre” at all, but an incorrect usage of the French “prix fixe,” meaning “fixed price.”)

There’s no logical reason for some of these “pre” uses. But then, few claim that English is logical. (Speaking of which, dictionaries and usage guides disagree whether to hyphenate or not to hyphenate “pre” in many of these uses, so we’re hyphenating for emphasis and consistency.)

How does one “pre-plan”? Planning, by definition, is before. For a kitchen renovation, one news story said, “You don’t want to go back in and start ripping and tearing again—you have to pre-plan.” Government agencies seem particularly fond of making “pre-plans.” They should just “plan.”

Similarly, how does one “pre-pay”? You’re paying. You may not get what you paid for, but you’ve paid. (Perhaps the word should be “pre-buy” or “pre-get,” not “pre-pay.”) And there’s no logic there, either: With mortgages, to “pre-pay” means to pay it off before its due date, not before you get the mortgage.

As for “pre-need,” well, most of us will need a funeral at some point. Paying for it before you need it may or may not be smart—one of the largest funeral sellers, National “Preassurance” Services, went out of business and its president has been charged with fraud. But there seems to be no need for a “pre-” before “need,” because without need, there is no need. And a “pre-fix” is really “pre-vention.”

Few dictionaries or usage guides discuss these “pre-ternatural” usages except anecdotally. Garner’s Modern American Usage calls “pre-plan” “illogical,” but the North American Oxford Dictionary accepts it unconditionally, as it does “pre-need” and “pre-pay.” Garner says “pre-owned” is “a common euphemism,” and Webster’s New World College Dictionary accepts it.

Just because they’re in a dictionary doesn’t create a pre-judice for using them. If a word or common phrase exists, there’s no need to use one that may not be understood by readers or creates a redundancy, or to “pre-create” a new one.

Merrill Perlman managed copy desks across the newsroom at The New York Times, where she worked for 25 years.