Every week or every other week. I never let it go longer than three weeks. In reality, God being very generous as always, in my present situation, there is no reason for me to not go every week. I forgot that there are many who can only go on rare occasion, so thanks for starting this thread! It reminds me and makes me resolve to go and get the graces every week as long as this great gift of God is available for me.
For those who don't know - you do not need to go to confession if you are without mortal sin, but even without mortal sin on your soul, you can still go to confession to receive the graces to help strengthen your resolve against future temptations, all you need to do to receive those graces is to simply say: "Forgive me father for I have sinned, my last confession was one week ago and I have not committed any mortal sins, but I need the graces father, so for all the sins of my past life especially for my sin(s) against ___________ I am heartily sorry, please forgive me father".