I used to press all seams open until I watched a video explaining seam strength. When pressing open, the thread is the weak link to holding the quilt together. When pressing to side, the fabric, which is stronger, is holding the quilt together. Made sense to me. Sooo, I developed a system for pressing seams using odds and evens (row number, etc.). Odd rows pressed to right, Even rows pressed to left. Some situations, however, call for open seams. I mostly SID, so no problems there.