Even if a live person is present, the automation system at commercial stations usually picks the music ahead of time out of the current rotation, thus the DJ becomes only an announcer.
Prolonged listening to a station that places songs in heavy rotation can quickly become unpleasant; such stations are not well-suited for retail environments, where employees must listen for hours on end multiple days a week, and doing so can breed contempt for the music and create a hostile work environment.
Recurrent rotation refers to a group of songs still frequently aired on a contemporary hit radio station several months or even years after the initial debut.
The Billboard charts include these lists: Songs that survive in recurrent rotation typically form the basis of radio formats as years advance.
A hit song that is left out of recurrent rotation will eventually become known as a "forgotten 45", a name derived from the fact that singles used to be released on 45 RPM records.