I have quilted that far apart and it's been OK. Generally I like more quilting but have made a few where I did either stitch in the ditch or straight row quilting, mostly when I first started quilting. They are all around, been washed and holding up well. My sister-in-law made a quilt for her husband and quilted it very sparingly. My brother-in-law washed the quilt years later and the batting shifted so that the quilt was useless. Since my sister-in-law was no longer around he gave the quilt to me to fix. I ripped the quilting out and put a new back on it as she had used some fuzzy material that was matted along with with a new batting. I tied that quilt because the patchwork was done in such a way that nothing matched much. I did tie it every few inches. What a job! The bottom line is it's OK to quilt as little as the batting instructions say but don't skimp beyond that.