The development of lay spirituality of adoration has led to some developments in worship.
132. Now, the Church in the course of centuries has introduced various forms of this worship which are ever increasing in beauty and helpfulness: as, for example, visits of devotion to the tabernacles, even every day; benediction of the Blessed Sacrament; solemn processions, especially at the time of Eucharistic Congress, which pass through cities and villages; and adoration of the Blessed Sacrament publicly exposed. Sometimes these public acts of adoration are of short duration. Sometimes they last for one, several and even for forty hours. In certain places they continue in turn in different churches throughout the year, while elsewhere adoration is perpetual day and night, under the care of religious communities, and the faithful quite often take part in them.
Interesting that Pope Pius mentions religious communities tending “perpetual” adoration. That adjective always struck me as somewhat proud, even if it is traditional. “Continuous” perhaps. “Constant,” too. Who knows if adoration will continue in a location forever. I wonder what the longest period of “constant” adoration has been.
What were once devotions of the laity, are now embraced top-to-bottom in the hierarchical Church:
133. These exercises of piety have brought a wonderful increase in faith and supernatural life to the Church militant upon earth and they are reechoed to a certain extent by the Church triumphant in heaven which sings continually a hymn of praise to God and to the Lamb “who was slain.”[Rev. 5:12, cp. 7:10] Wherefore, the Church not merely approves these pious practices, which in the course of centuries have spread everywhere throughout the world, but makes them her own, as it were, and by her authority commends them.[Cf. Council of Trent, Sess. 13, c. 5 and c. 6] They spring from the inspiration of the liturgy and if they are performed with due propriety and with faith and piety, as the liturgical rules of the Church require, they are undoubtedly of the very greatest assistance in living the life of the liturgy.
Thus we have an important reminder that among the most fruitful of devotions are those anchored in the liturgy of the Church.