DJ headphones — over, on or in-ear?
Cueing is a process that defines the modern DJ, even more so than other skills like being able to scratch or beat juggled. If you look at the history of scratching, you’ll find that it was actually discovered when a DJ figured out that what he was back-cueing in his headphones sounded good, and he decided to play the cued part live. The ability to cue audio, and hear what the audience cannot hear sets the stage for a DJ to create seamless mixes and build the emotion of a dance floor. Without good headphones and a mixer with capability, one would have a much harder time trying to line two songs up.
As far as cueing styles, there is not one agreed upon way to cue music, and there are many different styles – depending on what types of headphones are used. Over the ear headphones allow the DJ to keep one ear to the live sound, and another to his cued sound – but in ear headphones allows the DJ to fader his cue between both the master audio and the cued audio. Each technique has its own benefits and flaws, and one cannot be said to be better than the other.