Very interesting subject. I usually have one or two project going on in the same time. But the main reason for it is because I have small kids at home, so I have to adapt to what they are doing. I can only sew in the afternoon, while they are taking their nap. But when they are playing outside in our garden, I take my Fiskars, my dies and my fabrics outside too and I cut (an easy task to do while keeping them under my eyes). Having always something ready to sew or to cut is my way to be efficient (otherwise I would only be able to finish one or two quilt a year!)