Conversion happens once and one should continue to grow in knowledge and faith. I have grown in my level of knowledge, understanding and faith since I was baptized 50 years ago. this is how I interpret “conversion is life long.” If you prefer to see conversion as being the beginning and end of your journey with Christ, with no further study or desire to understand more deeply of Christ, so you have decided.
Agree.
Studying to learn and show ourselves approved and worthy is not a one-shot deal.
It’s a life-time journey.
You also misunderstand: sanctification is precisely the lifelong learning and depending of my faith. I have decided to follow Jesus, accepting the salvation He bought for me. If I have to crucify Him repeatedly, I make a mockery of His sacrifice “once for all”