Nobody likes to think of himself or herself as a sinner yet that is what we are. Though we are forgiven by God in baptism yet we continue every day to offend God by sinning. For a healthy spiritual life, never forget your sinful condition. Do not be overwhelmed or depressed by it. But do not forget, it is real.
A sin is an offence against God and His law. The New Testament gives a distinction between a mortal sin and a venial sin. The mortal sin is so horrible that it destroys the life of grace in the soul. (1 Jn. 5:16-17)
There are three conditions necessary for a mortal sin:
We Catholics are fortunate indeed to have the sacrament of penance, also known as the sacrament of reconciliation or sacrament of confession. This is the Lord's gift to His followers, given on Resurrection night as a ministry to the apostles to forgive or retain sins. (Jn 20: 19-23). So the ordinary way for us to have our sins forgiven is by this sacrament.
Knowing how' sin offends God, it is necessary therefore that everyone should go to confession regularly. But how often? The Holy Father, the Pope, goes to confession every week. The Old Catholic tradition requires that every Catholic goes to confession every month (before first Fridays) or every three months (Ember Days). If one commits a mortal sin, this grave sin, then one must immediately go to confession.
The Church obliges that we receive Holy Communion at least once a year, which means going to confession at least once a year (during the Easter season) for those in mortal sin. But for those who have not committed any mortal sit], going to confession once a year is not good enough, and twice a year a bare minimum. The Catholic who receives communion regularly should go to confession regularly.
Sacrament of confession or reconciliation or penance, is something awesome, something intensely personal, where we miserable sinners beg for God's mercy and forgiveness. It is a wonderful sacrament which keeps us humble, out of trouble, and working for holiness. To be sure that we have the mercy of God and His forgiveness, LET US GO TO CONFESSION REGULARLY, i.e. ONCE EVERY MONTH!!!