Posted by Fibbs

For that crate, since you're using the same texture for each side, you could just overlap the faces and use the entire UV space for one face.

This is true. I wanted to be able to make texture variations on this prop, such as having stuff written on the side or top of it. That is why I have 4 sides UV mapped. One of them is for the top of the crate, another for the bottom, and the sides are mapped to share texture coordinates with the opposite side.