Samantha’s husband Darrin was played by more than one actor. Without warning or explanation, producers replaced Dick York with Dick Sargent, apparently hoping the audience either wouldn’t notice or wouldn’t care. The act of switching out actors without explanation like this became known as “The Darrin Syndrome.” Poor Dick York left the show due to chronic back pain.
The Darrin switch took place after the show had already been on the air for three seasons. Audiences usually don’t take too kindly to such a massive switch of a main character, and the 1960s audiences were no different. Audiences noticed the difference, and ratings plummeted for the show’s final three years. Fans just weren’t willing to accept an unfamiliar face in the role.