David Crimmins, manager of the Lindquist Group, a residential staffing firm with offices in New York City; Greenwich, Conn.; Palm Beach, Fla.; and Atlanta, said: “I’ve had clients looking for someone with the ability to curate and catalog photos, to ghostwrite a book. Or they need an estate manager with a construction and engineering background, but they can hire the nanny, who of course has to have a background teaching early education. It can get very specific.”