"It's time for us to find an endpoint to the show," said Cuse, speaking Sunday at ABC's portion of the TV Critics Assn. press tour. "It's a struggle for us, because we don't know if we have three years, four years or more to go. If we had an endpoint, then we could figure out where everything goes."

Such a move would placate fans of the show, who frequently gripe that they have no indication whether the show's ever-increasing mysteries will pay off. A set timetable would send a message to viewers that all of their questions will be answered eventually.

"Once we figure out when that will be, a lot of those concerns will go away," Cuse said. "The worst point is when a show ends and no one cares. We don't want that to happen. We want to make the shows good for as long as we do the show."