i have made many rag quilts (as you can tell by my avatar -lol) i used to sew the x but then i read where depending on the size of the blocks (if they are under 8 inches) and depending on if you use flannel for all three layers there is no need to sew the x. lately i have been making them with just the top flannel and the bottom flannel - no batting between. it makes a lighter weight quilt but is quite warm. i am making two right now - one is large squares and don't know what i was thinking but forgot to sew the x so i may make a square in each one but the other one is smaller 5 inch squares - on that one i won't sew an x throught it. again it is purely a matter of choice.