My DS1 has long torso and lanky limbs. He is so skinny that he can still wear a size 4 shirt (except occasional malfunction wardrobe, revealing the tummy). It gets worst with pants as the correct size is super loose fit on him and a size 4 or 5, too short.
In fact his brother is catching up and started to take over his size 4 clothings!
This pants was made in attempt to finish up my fabric stash and I am glad I did so!
he looked so much more comfortable in them!