Does one have to confess their sins regularly, or before they are allowed to take communion? And why confess to a priest at all? Can't I just go directly to God in prayer?
The only requirement, as I understand it, is to participate in the "Sacrament of Reconciliation" -- and isn't that a nicer way to say it? -- once a year, in the Easter season. It is done before one's first communion as a new Catholic. It is not required before every communion (in fact, the reason there is a corporate confession in the Mass near the beginning is to sacramentally prepare everyone to receive Christ with a clean conscience). More frequent use of this sacrament - this 'contact point' with Christ - is encouraged. Some go every week, some monthly. I'm not there yet.
There are some who object to this practice completely, as you suggest, pointing to First John 1:9 and declaring that there is no need for a human priest or intermediary to hear a confession. While Catholics affirm the wonderful truth of that First John verse, they also take seriously Matthew 16:19 and John 20:22,23. These are verses I had always overlooked and avoided. But the meaning is plain. Christ entrusted to the apostles and their successors the authority to forgive sins in His name based on His all-sufficient merit. When a person meets a priest in this sacrament, he/she is meeting with Christ sacramentally. It is a scary - and powerful - and healing - encounter.
Historically speaking, early Christians were excluded from communion if they fell into sin (in keeping with First Corinthians 11:27 - you ARE looking up all the verses, right?) but upon repentance and restitution (if needed) they then proclaimed - ie, 'confessed' - to the priest that they were ready to participate once again. "Confession," in the way the ancient church used the word, was to PROFESS God's mercy.
The emphasis has changed over the years from imposing a 'penance' (like the rote reciting of a few memorized prayers - how empty) to assigning a positive action to heal any hurts caused and to improve one's plan to virtuously live the excellent life (a phrase Aristotle would have liked), and to grow toward Christlikeness. The idea isn't to somehow 'make up for' the sin - we can't - Christ paid the full price. The idea is to demonstrate a resolve to improve.
This is another good thing about the Church: there isn't this 'once saved always saved' attitude that can lead to bad behavior. Instead, there is a practical recognition that we still sin and fail and need to participate fully, cooperate fully, in the process of our full salvation. We must admit that there is a poor attitude among some Catholics that it's ok to sin as you please, since it can always be 'confessed.' These folks never read Romans 6, I guess. It's just as bad as the 'once saved always saved' business.
Maybe the sticking point is the religious word "salvation." This word appears next to the word "salvage" in a dictionary. Think of how a ship is salvaged, or a vintage car that has been left in a junkyard a long time. We have been salvaged from the depths of our ruin by the proper owner in a singular action (the cross and resurrection), but now we are in the longer process of being renewed to the beauty we were meant to have and restored to usefulness and our original purpose. This takes grinding and polishing - the grinding off of rust and mold and imperfections so we may be transformed into our intended state. That is what is going on in this sacramental practice.
"Salve" is the other word next to "salvation" in the dictionary, meaning to bring healing and wholeness. That's the other thing going on in this sacramental practice. I think it's a lovely thing.
Can you go to God directly? Yes. And we should. The Psalmist prays to God directly; King Hezekiah did; the publican did in the back row. But Christ Himself established this sacramental means by which we experience reconciliation with Him, and we who love Him - and wish to obey Him fully - take part in this practice with humble gratitude.