Unless I’m wrong confession in the early church was a rarer event, like it was done once and typically the penances were very, very long: maybe 6 months to a year. When did confession start being offered regularly and when did the penance start to change and why?
What does James say in the 5th chapter of his epistle?
That’s not what I asked, I’m not against confession as a sacrament I’m just asking when it became a regular practice as opposed to once a year or so. This can’t really be answered with a bible verse.
It started to change into a tariff system, which is an early iteration of what we have today, in the Irish monasteries beginning in the late sixth century and continuing until the Council of Toledo. Confession as we have it today, however, really did not being until the second half of the twelfth century with the influence of Aristotelean thought and an increased emphasis on the human person.
http://www.newadvent.org/cathen/11618c.htm
The (private) confession of even venial sins was lauded by St. Cyprian even in the third century.
I’m not sure where the myth that frequent confession started in Ireland came from.
History and Church historians.
Why did they change? I’m not sure what you mean
The Church’s canonical discipline (penalties for those found guilty of serious crimes like idolatry) became more lenient after the end of the Roman persecutions. That’s a distinct (though connected) matter to private confession and penance.
It was just a gradual development. At first, as you noted, Confession was only given for very serious sins (ie. the lapsy who renounced their faith during times of persecution). Then it gradually grew to those who committed very serious sins (i.e. murder, rape, incest), and it was only administered once on Good Thursday (the ashes on ash Wednesday formerly symbolized the beginning of the penitential process whereby the penitents would wear sackcloth and be covered in ashes).
Then the Irish monasteries began serving as spiritual and intellectual centers for those in Ireland. I forget the details, but somewhere in the process they developed a tariff penance system whereby those who committed a sin would go to them, receive spiritual direction and a penance, and he or she would presumably be forgiven once the penance was complete. We still have many, many copies of the penitential manuals from this period that very clearly indicate that confession was not as it is today.
Then during the reforms under Charlemagne it was decided that public sins would be confessed in public and private sins would be confessed in private or to a priest. During this period there were three divisions of penance: solemn public penance for serious sins, non-solemn public penance for less serious public sins, and private penance for private sins.
It wasn’t really until the second half of the twelfth century that Peter Abelard started emphasizing the subjective factors in human sin (i.e. the concept of inner sorrow or contrition being important). At this point, the role of the confessor shifted from merely assigning a penance (penitentials were becoming oh so confusing) and instead focuses on the contrition of the person confessing. It is also at this point in history that a declarative form of absolution developed (i.e. I absolve you from your sins in the name of the…).
Aquinas developed a rather sophisticated theology of penance, and by Lateran IV it was mandatory for all Christians once a year. It was also at this time that the relationship between confession and the Eucharist was officially affirmed.
I don’t remember which books I read to gather this information, but Remember that one was written by an Australian priest.
Because that’s when private confession took root. Frequent confession already existed, but let’s be real: if your priest stood up at Mass and said, “hey, anyone who wants to confess, please stand up and tell us your sins!”… would you do it?
So… frequent confession became common in that later timeframe, but it became normative much earlier.
Wouldn’t confession have more of an impact if it were practiced less frequently?
I don’t understand. How so?
I don’t know. It’s kind of like holidays. If they were every weekend no one would care.
No. Pope Leo the Great referred to the private confession of private sins as an “Apostolic rule”:
“Pope Leo the Great (440-61), who is often credited with the institution of confession, refers to it as an “Apostolic rule”. Writing to the bishops of Campania he forbids as an abuse “contrary to the Apostolic rule” (contra apostolicam regulam) the reading out in public of a written statement of their sins drawn up by the faithful, because, he declares, “it suffices that the guilt of conscience be manifested to priests alone in secret confession” (Ep. clxviii in P.L., LIV, 1210).”
But since it is a sacrament, we receive real grace each time we go! We wouldn’t want to limit that grace to just a few times a year. I need it, well, like monthly!
That would absolutely kill scruples. They wouldn’t leave their homes in fear of a fatal accident or something.
Well you can receive grace with perfect contrition too

No. Pope Leo the Great referred to the private confession of private sins as an “Apostolic rule”:
So, like I said: it became normative earlier, but common later.
One should always have perfect contrition after a sin, and a confession is not valid without it.
It is quite impious to deny oneself the grace that is received specifically by confessing often. Every venial sin you commit will weaken your relationship with God and the state of your soul, and perfect contrition is not sufficient to restore that completely.
Also holidays are every weekend, even every day. Today is the Feast of Saints John and Paul. While this feast may not be as important as Easter or Christmas, it is certainly beneficial to celebrate this day as well, and indifference to it would be most unbecoming of any faithful Christian.

One must always have perfect contrition after a sin, and a confession is not valid without it.
This is incorrect.
"As to imperfect contrition, which is called attrition, since it commonly arises either from the consideration of the heinousness of sin or from the fear of hell and of punishment, the council declares that if it renounces the desire to sin and hopes for pardon, it not only does not make one a hypocrite and a greater sinner, but is even a gift of God and an impulse of the Holy Ghost, not indeed as already dwelling in the penitent, but only moving him, with which assistance the penitent prepares a way for himself unto justice.
And though without the sacrament of penance it cannot per se lead the sinner to justification, it does, however, dispose him to obtain the grace of God in the sacrament of penance."