In very early DS, which the Watching Project is on right now, usually there's no repeated scene at all. Later, the repeated scene was almost always re-shot, since apparently making the actors do it all over again was cheaper than editing in a copy of the previous day's scene. Much later as the budget went up a bit, there were more edits in the show in general, such as during Parallel Time, where the concept demanded it, and I think there were fewer re-shot openings then.