On spiritual exercises and retreats:
178. Take special care that as many as possible, not only of the clergy but of the laity and especially those in religious organizations and in the ranks of Catholic Action, take part in monthly days of recollection and in retreats of longer duration made with a view to growing in virtue. As We have previously stated, such spiritual exercises are most useful and even necessary to instill into souls solid virtue, and to strengthen them in sanctity so as to be able to derive from the sacred liturgy more efficacious and abundant benefits.
Before retreats became a corporate thing, they were frequently offered and promoted. My first experiences of them were as a Catholic Scout–seminarians planned them annually for us. In high school, the occasional day of recollection. In the parish–nothing. It wasn’t until my college experience and our regular visits to the Trappist monastery that I experienced the first spiritually significant retreats.
179. As regards the different methods employed in these exercises, it is perfectly clear to all that in the Church on earth, no less in the Church in heaven, there are many mansions,[Cf. John, 14:2] and that asceticism cannot be the monopoly of anyone. It is the same spirit who breatheth where He will,[John 3:8] and who with differing gifts and in different ways enlightens and guides souls to sanctity. Let their freedom and the supernatural action of the Holy Spirit be so sacrosanct that no one presume to disturb or stifle them for any reason whatsoever.
Lots of variety, but Ignatian spirituality is commended:
180. However, it is well known that the spiritual exercise according to the method and norms of St. Ignatius have been fully approved and earnestly recommended by Our predecessors on account of their admirable efficacy. We, too, for the same reason have approved and commended them and willingly do We repeat this now.