I’m a former Protestant and was pretty dedicated as one. I was homeschooled and had Bible class daily. I started studying Scripture when I was fifteen, and my family did family Bible readings for years. These included the daily Proverb and a reading from a selected book. I’ve also been in numerous Bible studies. Some were simply passionate teenagers. Others were officially put on by the church, ranging from Presbyterian to Catholic ones.
With all that said, I’d imagine that I know my Bible better than most. That said, I still am admittedly ignorant of a lot of it and am constantly surprised by little details I missed the first hundred times. I also haven’t read all of the Catholic-specific ones. So far, I’ve only read Tobit and Judith in full.