It depends on the aim of the learner, for example if somebody is going to take a TOEIC/TOEFL and other tests, he have to bear in mind that listening/reading/writting go hand-in-hand.    Other example, there are situations in wich one has to  read, and reading helps to build up vocabulary, one thing leads to another.

     I think that the name of the game is trainning, practice makes perfect, that´s why my skills are so rusty!