I know it takes extra time, however, when I'm working with a quilt with lots of smaller parts making a whole, I square them up as I sew them. It seems like a waste of time, however, when I go to sew them together into the block, they fit almost perfectly. I could probably eliminate the trimming if I slowed down a bit, however, I also sew a little bit at a time, so it's not perfect. To me, trimming is part of the whole process and in the end only takes a little bit of time, with great results.