baggers44 All in your head mate. Thats what ‘knowing your tunes’ is really all about. Knowing what will and won’t work, knowing where the phrases and percussions change, knowing that the esoteric floaty breaks track you love really, really, really won’t mix into the Rotterdam techno track you also love…
What you will find a lot of DJs do to negate some of these issues is to play very narrow genre selections, so, you go and see a ‘chicago house DJ’, they will probably play just chicago house, 100% of their tracks will be chicago house and 70% of those tracks will work perfectly well into each other, they may have a few vocal clashes they need to avoid, but otherwise it will all work quite well and they can make it up as they go along. When I used to play six hours etc, i’d break it down into smaller sets with tunes that I know worked together.