If your squares are constantly off in measurement, check your seam allowance. There lies the truth. I am completing a lovely, labor intensive quilt from Japanese Quilt Inspirations by Susan Briscoe and found that I could see the variance immediately so I began to check each piece when the seam was finished with my small Dritze Ruler to improve accuracy. I would make corrections right away, not wait until the block was finished. All I have to do now is press the last two borders and it is ready to be admired....and sent to the quilter as it is 75" square....a lot for me to handle. I will be 75 years old this week and feel this could be my Swan Song....the best ever. It is worth the extra effort to be satisfied with the work of your hands.