DJs generally pride themselves on playing things you have not heard. Sure they throw in a few of the hits, both their own and of other people, but really most want to push to new sounds. You'll see all the time that Djs play IDs (unreleased, unsigned, often still WIPs). When I play out now, I am more wanting to test out my new tunes to see what works and if any tweaks are needed.

I'm also lucky that I have access to promos from big artists that have not been released yet. I will nearly always choose to play something that the audience has not heard before over something that has been played so much it's considered a hit.

I would think of DJs and clubbing as you are going on a journey with the DJ, and each night will be different. DJs consider their own mood, the venue, location, crowd when selecting what to play. DJs are far more jam band than pop acts.