 Currently, sixty-minute episodes (from September 1980-May 1992) air Monday through Friday nights, and ninety-minute episodes (from 1972-September 12, 1980) Saturday and Sunday nights.Jack Paar had often asked Carson to guest-host "Tonight" in its earliest years and repeatedly claimed he had been responsible for NBC's selection of Carson in 1962 as his replacement.Steve Allen also utilized guest hosts, including Carson and Ernie Kovacs, particularly after he began hosting "The Steve Allen Show" in prime time in 1956 and needed to reduce his workload on "Tonight".