Or, ask it another way, do you find the launcher downloaded pre-compiled engine enough for real game development?
Thanks!
I started hacking around the source code about a month into development.
You hit this requirement faster if your product implements multiplayer components.
Other than that, is usually simpler to build a plugin for UE4 instead of modifying engine code. I’ve been building private plugins for teams whose prefer using the launcher pre-compiled engines, they simply don’t want the extra headaches added by building the engine from source and I believe they are right: focus on the game 
I prefer to extend classes and override methods where i sometimes copy and modify the engine code for custom functionalities.
Main reasson i prefer not to modify the source itself is to stay compatible when switching to newer version of the engine
I would love to constantly make changes, except for the fact that I would have to recompile, and I’m not as experienced as I’d like to be in C++.
I try to stick with making C++ plugins that either expose classes or BP nodes, so I can easily move to a new version without recompiling the whole engine.
I try to avoid it is as i don’t want to have to deal with merging my changes with Epic when ever I want to update the engine, so so far like others here I do extensions/modifications with plugins.
That said I think I’m about to hit an issue where I’ll have no choice but to dive in and modify the engine (ligthmaps on translated streaming levels).
Game modules or plugins are the way to go then you can take your code to other projects. Also when a new version of the engine comes out you’re not having to redo your changes if you wish to upgrade to that new version.
Feature request is also a good option in some cases. Then you will have experienced programmers working on your feature if it is taken up by Epic.
Plugins all the way!
Haven’t hit a bump where I needed to modify the engine… yet, but I’m sure the day will come though.
Thanks to all of you