From these quotes it is abundantly clear that St. Louis de Montfort was recommending a full fifteen decades to adults. Yet people he was speaking with on missions were often hardened sinners, just beginning in their faith and conversion.
Why start with the Holy Rosary? Because frequently that is where people start deepening their spiritual journey. After praying a Hail Mary, and then a decade of the Rosary they begin to pray more. Eventually they can work up to going to daily Mass and adoration, all depending on their state in life.
The Rosary is the door to the rest of a full catholic life and life in heaven.
A Red Rose: For Sinners
“By all means, then, let us recite the entire Rosary every day, that is to say, three rosaries each of five decades, which we can liken to three garlands or crowns of flowers. We should also meditate on its more profound meaning…”
A Rosebud: [a message to children]
“Dear little friends, this beautiful rosebud is for you; it is one of the beads of your Rosary, and it may seem to you to be such a tiny thing. But if you only knew how precious this bead is! This wonderful bud will open out into a gorgeous rose if you say your Hail Mary really well. Of course it would be too much to expect you to say the whole fifteen mysteries every day, but do say at least five mysteries, and say them properly with love and devotion. “
“The Rosary is made up of two things: mental prayer and vocal prayer. In the Rosary mental prayer is none other than meditation of the chief mysteries of the life, death and glory of Jesus Christ and of his blessed Mother. Vocal prayer consists in saying fifteen decades of [the Rosary]…”
Fifth Rose: Confraternity
“Strictly speaking, there can be only one kind of Confraternity of the Rosary, that is, one whose members agree to say the entire Rosary of 150 Hail Marys every day. However, considering the fervour of those who say it, we may distinguish three kinds: Ordinary Membership, which entails saying the complete Rosary once a week; Perpetual Membership, which requires it to be said only once a year; Daily Membership, which obliges one to say it all every day, that is, the fifteen decades made up of 150 Hail Marys.”
Twenty-first Rose: The Fifteen Mysteries of the Rosary
Our Lady taught Blessed Alan de la Roche and said to him in a vision:
“When people say 150 Hail Mary’s, this prayer is very helpful to them and is a very pleasing tribute to Me.”… “But they will do better still and will please Me even more if they say these Hail Mary’s while meditating on the life, death and passion of Jesus Christ – for this meditation is the soul of this prayer.”
Twenty-Fifth Rose: The Wealth Of Sanctification
…if you are still in the state of active contemplation or the ordinary prayer of quietude, or the presence of God, affective prayer, you have even less reason for giving up the Rosary. Far from making you lose ground in mental prayer or stunting your spiritual growth, it will be a wonderful help to you. You will find it a real Jacob’s ladder with fifteen rungs by which you will go from virtue to virtue and from light to light. Thus, without danger of being misled, you will easily arrive at the fullness of the age of Jesus Christ.
“…I advise you to divide up your Rosary into three parts and to say each group of mysteries (five decades) at a different time of day. This is much better than saying the whole fifteen decades all at once.
If you cannot find the time to say a third part of the Rosary all at one time, say it gradually, a decade here and there. I am sure you can manage this; so that, in spite of your work and all the calls upon your time, you will have said the whole Rosary before going to bed.
Saint Francis de Sales sets us a very good example of faithfulness in this respect: once when he was quite exhausted from the visits of the day and remembered, towards midnight, that he had left a few decades of his Rosary unsaid, he would not go to bed until he had finished them on his knees, notwithstanding all the efforts of his secretary who saw he was tired and begged him to let the rest of his prayers go until the next day.”
The Power, Value And Holiness Of The Rosary:
A Revelation of Our Blessed Lady to Blessed Alan de la Roche
“Having been strongly urged to do so by Saint Dominic, all the brothers and sisters of his order honored [Mary and her Son] unceasingly and in an indescribably beautiful way by saying the Holy Rosary. Every day each one of them said at least one complete Rosary. If anybody failed to say it he felt that his day was entirely spoiled.
The Brothers of Saint Dominic had so great a love for this holy devotion that it made them do everything better and they used to hurry to church or to the choir to sing the office. If one of them was seen to carry out his duties carelessly the others would say with assurance:
“Oh, Brother! Either you are not saying Mary’s Psalter [the Rosary] any more or else you are saying it badly.”
“…After the Holy Sacrifice of the Mass, there is nothing in the Church that I love as much as the Rosary.”
-Our Lady to Blessed Alan de la Roche
“…Reciting with attention, devotion and reverence the fifteen decades of the Rosary in honour of the fifteen principal mysteries of our Lord, or at least five decades …”
From “True Devotion to Mary”
Part I: True Devotion To Our Lady In General (cont)
Ch 2: In what Devotion to Mary Consists (cont)
3. Principal practices of devotion to Mary