I don't know if anyone does this, bit when I want to conserve paper in my sketchbooks, I don't draw on the back physically on each page, but rather doodle/scribble on sheets of loose paper,cut them out,and paste them on the back of previous pages. Other wise, I just use one side of each page and move on to the next.
Graph paper fun featuring #spazjackrabbit of #jazzjackrabbit fame, a bear running after something, and a gorilla in sailor garb. This method helps me to save on not physically drawing on the back of each page in my sketchbooks.