Praying the Rosary well should be one’s primary concern.
A good quote about doing what’s immediately required of us:
It is true, considering things in themselves, that the conversion of a soul is, without doubt, infinitely more acceptable to the Divine Majesty than the mortification of a disorderly affection. Yet, every person, in his own particular sphere, should begin with what is immediately required of him. Now what God expects of us, above all else, is a serious application to conquering our passions; and this is more properly the accomplishment of our duty than if, with uncontrolled appetite, we should do Him a greater service.
St. Louis-Marie promises that if we pray and preach the Rosary, we will learn more from it than from books. Rosary is the Rose of methods of prayers, (it is the best) and therefore experience in praying the Rosary and finding out how to pray it will profit us more than from reading spiritual books.
There is certainly nothing more useful than prayer.[remember that Rosary is the prayer of prayers] Therefore, we ought to entertain great esteem and love for it, and employ every effort to make it well.—-St. Vincent de Paul
The incorrupt saint St. Germaine’s only ‘book’ was the Rosary.
Since studying anything other than that relates to the Rosary, (when one has not yet attained perfect spirit of prayer of the Rosary) is not GOD”s WILL, GOD will punish our substantial diversions to even good things (such as reading a non Rosary related book at the time at which I should read more about the Rosary and think about the Rosary and writing down how to pray it).