Our fall fair judge wrote on some entries that there should be no space larger then your hand in your quilt that wasn't quilted. She seemed to think that a quilt not quilted densely enough would eventually fall apart. This has not been my experience and I have definately found that quilts not quilted quite so closely are more cuddly. Some of the newer types of batting even say that your quilting lines may be up to 10 inches apart. If you are trying to win prizes at shows it seems that dense quilting is mandatory to have any chance of a ribbon. It all comes back to your preferences as a quilter and the ultimate purpose of the quilt. The heirloom wedding quilt may need more quilting than the couch quilt that your son and dog snuggle under.