Brendan Moody wrote:
Yeah, on past patterns Martin should be able to deliver Winds before the producers need it, if only just, but they're going to have to start taking breaks between seasons if they want to wait for A Dream of Spring. And that's without getting into the possibility of the series going to eight books...
And the producers said in one of their recent interviews that they're not going to take any breaks. They also said trying to stretch the show to 10 seasons would be too much.
I'm confident that the show will have an ending and won't be cancelled and left hanging, but there is a chance that HBO and the producers will evaluate the situation after the fourth season and decide to go their own way and wrap things up in five or six seasons.