John Piper pleas for…
Both:
Daily prayerful meditation seeking personal application of God’s word to your own heart and life.
And:
Regular study in a class or with a book where the (living or dead) teacher has seen more than you have and can give you insight in 30 minutes that might otherwise take you ten years to see.
Read more at A Plea for Heart Devotions and Head Study :: Desiring God.