I agreed with SewCrafty and KarenPatrick. It is very important to know what the manufactures of the different battings recommend as to how far apart the quilting stitches should be. Especially if you want the batting not to shift as the years go by. Years ago I made a longstar quilt (my first quilt) and did not quilt it as close as it should have been. Now the batting has loose areas, is wadded up in some areas, and has no batting at all in other areas.
"Fancy" quilting does not have to be SID or grid stitched first, but if you plan to do very close quilting in some areas it sure does help to stablize the quilt sandwich by stitching somewhat evenly over the entire quilt whether it is SID in sashing seams or outline stitching blocks. This will help keep the quilt square and avoid wavy borders. Of course, my experience has come from quilting on a longarm machine. Handquilters and domestic machine quilters may do it differently