Performance is the keyword when discussing UV and UVW mapping, which essentially involves mapping a 3D/2D mesh with textures—or, simplified, a naked body with no skin texture. There are many methods, which might also become many when shaders are invited to the party. The only limitations are what the game engine supports and doesn’t support. You will probably look into these things when making game assets at some point since this isn’t so much for those who just render out a scene to video or picture using rendering engines that come with such applications as Blender, 3ds max and similar.
The video below will give a general overview of mapping methods. The next one will go much more into this topic, now about texture arrays.