The anthology format meant that a new story and new characters would be introduced each week and this made the show expensive. In later years recurring characters and multi-part episodes became common. Throughout its run it was always in danger of cancellation and episodes appeared sporadically and with wide variations in quality. At its best the show represented some of television's finest moments, and paved the way for the groundbreaking Hill Street Blues and its successors including NYPD Blue and Homicide: Life on the Streets.