This is a vital question today where there has been a diminishing of the frequency and importance of Confession, at least in comparison to the 1940s and 1950s. To answer your question briefly, the Church requires Confession once a year for serious sin (mortal). For human failings that fall under the less serious sin (venial) category, the frequency of Confession is left to one's judgment.
To help you make that decision, I would like to reflect on the meaning and value of the sacrament. Theologians say we cannot discuss sacraments without accepting Christ as the primordial sacrament, that is the original, the first in order, and the Church as the fundamental or basic sacrament.
What does this mean? The sacraments are gifts of a loving God. They are occasions of grace through which God freely gives us love and mercy, presence and life. Whatever we can do is through God's grace and in response to this initiative of God.
Reconciliation as a sacrament evolved gradually in the Church. In the early years, there were even some disagreements about any forgiveness for serious sin after Baptism, especially for those who defected in the face of persecution. After about the year 150, a ritual developed for serious sinners whose public penance sometimes lasted for several years.
Around the year 1000, Irish missionaries brought a private form of Confession which gradually developed to include forgiveness of all sins, not just serious ones and which could be received more frequently. Only in 1215 at the Fourth Lateran Council did the Church officially adopt this form.
We need to understand that the sacrament of Reconciliation is primarily God's action, not the priest's or the penitent's. Only God can forgive sins and Jesus is centre stage in the process of forgiveness. This sacrament is the work of the Holy Spirit who is the giver of grace and blessing.
Reconciliation is a ritual whose main celebrant is the entire Church. The Church is a reconciling reality in its prayer, its life, in everything the Church does and that Christians do. The living Church, the parish community, should be a sacrament of a compassionate God.
When the lived Church experience and the sacrament of Reconciliation do not reinforce each other, the latter usually will have little meaning.
It is also important to remember that all sin is an offence against others as well as against God. In the same way, reconciliation is with others as well as with God.
The role of the penitent in the form of the sacrament that we practise today is contrition, confession and satisfaction or penance. In preparation for Confession, reflection on one's life and actions brings one to see God's goodness more clearly.
It is interesting to note that holy people often consider themselves very sinful in contrast to the rest of us ordinary mortals. Is it because they are much more aware of the depth of God's love for us and of their lack of gratitude?
Confession of our sins acknowledges God's compassionate love and our failure to respond. It is only through God's grace that we are able to repent and confess our sins.
There is another aspect to confessing the wrongs we have done. When we verbalize or write down something, we begin to understand ourselves better. We experience a renewed sense of God's love and feel more at peace, especially when we receive God's assurance of forgiveness in absolution. Isn't it marvellous that the Church offers us so many opportunities to grow spiritually?
Recently I read about Protestants coming to Confession to a Catholic priest for this reason. Although they didn't receive sacramental absolution, they received a prayer for God's forgiveness and felt at peace with God and themselves.
Today with the catharsis enjoyed by many who make public confessions on television and even on the Internet, it is time for Catholics to take another look at the blessings received through more frequent use of Confession.
How often should that be? Communal penitential liturgies are commonly held during Advent and Lent when we try to prepare for the feasts of Christmas and Easter. These are good practices when we celebrate this sacrament as community, as Church like we do the other sacraments.
During the rest of the year, we go when the Spirit moves us or when we feel the need. That may be monthly or more or less often. The only danger to watch for is scrupulosity where some people see sin where there is none leading them to too frequent Confession.
The important point to remember is that in the sacrament of Reconciliation, as in all sacraments, we receive that special grace and gift of renewed life from God. This helps us live daily with a stronger sense of God's presence and love, as well as a better understanding and firmer commitment to be other Christs for our world.