I agree with darth, that using large textures should be saved for things that really need them, and trying to make a lot out of smaller textures (and then layering over other things to give more variation like dirt for instance) is a better approach.
This doesn’t work for all textures. I think the issue I sometimes run into is that textures I don’t want to get destroyed by mipmapping, when the object is at a distance get blurred far too much, and for some reason the engine doesn’t switch those objects to the higher resolution when up close. When this happens, and my object (in this case a character that looks completely blurred up close) I find the texture map in UE4, and then at the Level Of Details, where it says Mip Gen Settings, I turn mipMapping off by setting it to NoMipMaps.
I wouldn’t recommend doing this for everything in your game, as it helps to keep the images cleaner when farther away, and help reduce the overhead you carry in the game during game play.
Keep in mind for my game too, I am trying to create a game that still looks very textured even when I have the Engine Scalability Settings setting the Texture quality to Low. So overall, I am trying to crunch my textures to keep my game running at a decent speed, but then I pick a couple things and turn off the mipMapping (although I’m skeptical that this always works - sometimes it ignores my setting and I’m not sure if it’s getting an override from the Scalability settings, but it’s currently unclear since it comes and goes).