I don't backstitch because it builds up thread in the seam, and will cause some distortion when bringing seams together. If you are conserned, reduce your seam length when piecing, or just at the ends where you are concerned. We I'm piecing I reduce the seam length to 2 from a preset 2.5. I haven't had a problem, but it does make it more tedious to rip if I need to. Can't have both!