Just to further derail things (I hope this doesn't get too far out) I think that's one of the things that makes soap operas such a good training ground. I've heard stories of soap stars being handed the day's scripts when they come in for makeup work. Even if that's an exaggeration, learning a script on the fly has to be valuable, not only as training in the craft, but also in terms of keeping things in perspective as an actor moves up the ladder toward bigger and better things.
Whatever one thinks of soaps (and I think decent writing at that rate is simply not possible, and decent acting almost as hard) soap actors are heroes... in the ancient Greek God sense of heroes, namely they do the humanly impossible. James Franco asked to be on a soap (General Hospital) for precisely that reason. I cannot imagine doing a soap for a week, and these people do it for years, often until a week or two before they literally DIE. They are marathoners, and I take my hats off to them. I'd love to hear Gene Francis and Jonathan Frakes have a conversation about learning lines. Yikes!