Every t-shirt quilt I've made I have used interfacing...Makes the blocks much easier to handle and sew. My first two quilts I stitched-in-the-ditch to quilt. I have had the others done by a long-arm quilter, and any others I will do the same. (My own machine does well with the quilting, but I'm limited for space and can't leave the machine set up long in one place.)