Please help to settle an argument. Just as "200 hours' community service" or "a moment's notice" require apostrophes to indicate possession, I believe "FIVE YEARS' VIP SERVICING" also merits one ("VIP SERVICING OF FIVE YEARS"). A copywriting colleague has got rather confused over his participles, gerunds, verbs and subjects. He fails to see the logic of testing the case by using an obvious singular-- eg, in "A YEAR'S VIP SERVICING" the "S" is clearly there to indicate possession rather than a plural. Can anyone help provide a straightforward explanation?