Each visit removes mortal sin from the soul and bestows graces on the soul.
That presumes that the penitent has a mortal sin to confess. The thread is asking about confessions made when there have been none to confess.
Many people falsely believe that reconciliation can be neglected if one is not in mortal sin, since, according to the Compendium of the Catechism of the Catholic Church:
Holy Communion increases our union with Christ and with his Church. It preserves and renews the life of grace received at Baptism and Confirmation and makes us grow in love for our neighbor. It strengthens us in charity, wipes away venial sins and preserves us from mortal sin in the future.
Nevertheless, the Holy Father has been adamant about the connection between the Sacraments of Eucharist and Reconciliation:
Consider this statement, included in
Sacramentum Caritatis:
The Synod recalled that Bishops have the pastoral duty of promoting within their Dioceses a reinvigorated catechesis on the conversion born of the Eucharist, and of encouraging frequent confession among the faithful. All priests should dedicate themselves with generosity, commitment and competency to administering the sacrament of Reconciliation. (60) In this regard, it is important that the confessionals in our churches should be clearly visible expressions of the importance of this sacrament. I ask pastors to be vigilant with regard to the celebration of the sacrament of Reconciliation, and to limit the practice of general absolution exclusively to the cases permitted, (61) since individual absolution is the only form intended for ordinary use. (62) Given the need to rediscover sacramental forgiveness, there ought to be a Penitentiary in every Diocese. (63) Finally, a balanced and sound practice of gaining indulgences, whether for oneself or for the dead, can be helpful for a renewed appreciation of the relationship between the Eucharist and Reconciliation. By this means the faithful obtain “remission before God of the temporal punishment due to sins whose guilt has already been forgiven.” (64) The use of indulgences helps us to understand that by our efforts alone we would be incapable of making reparation for the wrong we have done, and that the sins of each individual harm the whole community. Furthermore, the practice of indulgences, which involves not only the doctrine of Christ’s infinite merits, but also that of the communion of the saints, reminds us “how closely we are united to each other in Christ … and how the supernatural life of each can help others.” (65) Since the conditions for gaining an indulgence include going to confession and receiving sacramental communion, this practice can effectively sustain the faithful on their journey of conversion and in rediscovering the centrality of the Eucharist in the Christian life.