The calendar is not perfect, as the orbit around the sun is a bit more than 365 1/4 days, pushing things around. That why the century years (1800, 1900, 2000, etc) are not leap years unless evenly divisible by 400. Even then, the calendar is creeping out of sync ever so slightly.
When I was young, we had CBS, NBC, ABC, CBC, PBS, and one independent. We were in metro Detroit, giving us such a variety in over the air stations when most markets were lucky to have two.
No continuity staff…