Those of us past 65 probably have some memories of tacking a quilt. All of the family would gather around and tye about every 3 to 4 inches apart. My quilting group does the same thing when we do our charity quilt. It must be close enough together to hold it secure. I prefer mine about every 3 inches apart. I have one made and tacked over 30 years ago and its still in my car. It has a fun life as we use it a lot. Best of luck to you. Marvel