>>84855387Depends on the era. Now-a-days it's a lot of messing with sound levels, hitting a loop on a repeater box for some added sound, swapping songs on the list to change the set on the fly depending on crowd reception, and a few other things.
Way back when, you'd have to swap discs while also making sure to line up the right shit, add effects with a much more primitive setup (which is back when record scratching was popular), and still also mess with volume levels when you'd do stuff like track mashups with sound being input from both discs.