For example; people using Unity, GameMaker, etc have very little prep as all the tools are integrated, compared to those not using IDEs who have to sort out all sorts of dependencies, libraries, build systems, etc. Things like that shouldn't have to be done to any specific jam time, if they was you'd pretty much end up doing the same thing again for every jam.
If you're doing the same jams all the time, yeah. I've personally never made a 64x64px game, and Unity doesn't exactly handle that perfectly out of the box, so that's something I've been looking into beforehand.