This mod expands upon the very beginning of the game, stretching out the burner and bootstrap phase so that you actually need to use burner infrastructure, at least for a while.
However, unlike other mods which end up being something of an overhaul to accomplish this, EE uses a very low-profile "zero changes after you complete the techs" design; once you have passed the early game, your experience will be [i]exactly[/i] the same as it otherwise would be. Even all of your burner machinery should be 1:1 upgradeable to their "standard" variants.
There is an optional (enabled by default) additional tech which gates even the belts and burner inserters, to really drive home how much better things are once you automate.
Overall, this mod adds between 30 and 90 minutes to a playthrough, most to all of it in the burner phase.
Do note that this means your early game will consume a LOT more fuel than usual.