https://www.metv.com/stories/the-laughs-were-no-accident-on-the-dick-van-dyke-show

The production used some innovative techniques to keep the show fresh.

According to a 1961 article in the Meriden, Connecticut Record-Journal, the show would have two complete run-throughs of each script on consecutive nights, with a full audience in attendance. The first evening would tell the writers where jokes hit and where they were left wanting. The following evening, with the scripts punched up, the show would be again performed for a crowd, this time with a three-camera setup recording the episode. While this style of "dress rehearsal" attended by an audience would later be used in shows like The Carol Burnett Show and Saturday Night Live, back in '61, The Dick Van Dyke Show was the first.