There are the five mandatory and minimal requirements for catholic Christian life that ensure necessary prayer, moral effort, and growth in love of God and neighbor. Across Church history, there have been lists of more or less, but the content come from Mother Church to ensure her children practice the “bare minimum” for maintaining a spiritual life and to foster growth in the life of faith. These are part of Church law and found in the Catechism of the Catholic Church (CCC 2041-43) and a Christian neglectful of these of these (especially participation in holy Mass and confession) can constitute grave matter/ grave sin.
From the Catechism (2042-3):
The first precept (“You shall attend Mass on Sundays and holy days of obligation.”) requires the faithful to participate in the Eucharistic celebration when the Christian community gathers together on the day commemorating the Resurrection of the Lord.
The second precept (“You shall confess your sins at least once a year.”) ensures preparation for the Eucharist by the reception of the sacrament of reconciliation, which continues Baptism’s work of conversion and forgiveness.
[Remember, we should not present ourselves to receive holy Communion if we know we are in the state of serious mortal sin before getting ourselves to confession. Even if in serious sin, we must pray holy Mass and just not receive holy Communion. Holy Communion is the sacrament for the reconciled, not the sacrament of reconciliation.]
The third precept (“You shall humbly receive your Creator in Holy Communion at least during the Easter season.”) guarantees as a minimum the reception of the Lord’s Body and Blood in connection with the Paschal feasts, the origin and center of the Christian liturgy.
The fourth precept (“You shall keep holy the holy days of obligation.”) completes the Sunday observance by participation in the principal liturgical feasts which honor the mysteries of the Lord, the Virgin Mary, and the saints.
The fifth precept (“You shall observe the prescribed days of fasting and abstinence.”) ensures the times of ascesis and penance which prepare us for the liturgical feasts; they help us acquire mastery over our instincts and freedom of heart.
The faithful also have the duty of providing for the material needs of the Church, each according to his abilities.