Resizing the UV or the texture?

Let’s say I want to make the texture repeat twice, I can do it in two ways I think, the mapping coordinate thing in nodes and by simply making the UV island double larger, the second method is my preferred one due to less fixing needed when exporting to other software, but…should I do it like this or is this a ,no-no"? Reason why I am asking is that I usually see game textures that have loads of UV islands shrunk to fit a single image with multiple textures, but what I am doing is the opposite, using just one texture and having the island expand more than the texture itself.

No one, such a simple question and no one knows the answer?

It depends on how you’re planning to use (and/or how the engine deals with) the UV’s.
But both ways are acceptable, as long as they produce what you’re looking for.