I'm one of those people who have to make the block as perfect as I can, and I will re-do it, and re-do it until it's the very best I can do. Once the quilt is done and quilted though, then it's done, and any imperfections are just "variations". If I needed to change something major, I'd do a new quilt rather than spend time "un-sewing" at that point. I need to finish projects, and it would be so boring to have to take apart most of a project in order to fix it. Which is why I'm so fastidious about making each block perfect. I shouldn't have to "fix" a whole quilt after that!