"however you can have a list of tracks to be played during the gig"
Thats what I did in my last party

I made a list of tracks, with their BPM, so I can mix easily
playlist never works, you should play depending on the dancefloor mood.
Tiesto played "Forever Today" as "encore".
But some DJs plays the same song twice & even more, which is a really bad idea, even if its a good song , & some people who knows nothing of DJing, they will have bad thoughts about him.
"Burn their homes and churches. Then see if they will not laugh, sing and pray again. For when two of them meet anywhere in the world, see if they will not create a NEW ARMENIA..."
William Saroyan