It's especially true for writing.
Yes quite true. When I graduated from highschool my friends got me workbooks. They were essentialy childrens books where you had to write the same character again and again and again. I carried that book everywhere I went and whenever I had a spare moment I practiced. As a result, I can read and write Japanese fairly well. (I'd rate myself at a 3rd/4th grade level. Can't read a newspaper well tho)