creased

 Consider "Laker gets further thirty days credit" (Times headline); "Mr. Taranto, who had nineteen years service with the company.. ." (New York Times). The words should appear as days’ and years’. Alternatively, we could insert an of after the time elements ("thirty days of credit," "nineteen years of service"). One or the other is necessary.

 The problem is often aggravated by the inclusion of unnecessary words, as in each of these examples: "The scheme could well be appropriate in twenty-five years time, he said" (Times); "Many diplomats are anxious to settle the job by the end of the session in two weeks time" (Observer); "The government is prepared to part with several hundred acres worth of property" (Time magazine). Each requires an apostrophe. But that need could be obviated by excluding the superfluous wordage. What is "in twenty-five years’ time" if not "in twenty-five years"? What does "several hundred acres’ worth" say that "several hundred acres" does not?