Depends on your batting. Read the instructions on the bag. Some will tell you what size of stitching should be used. If it is the type that won't bunch up to much I would quilt every other strip just to get it it done faster. The old cotton batting our grandmothers used had to be stitched every inch. Good batting nowadays can be stiched 3 or 4 inches without trouble. Does this help. I've made a log cabin using a flannel blanket as filler and just stitched aroung each 12 inch square.