I would not hesitate to use the same design to make another quilt. You don't intent to make a copy, you're going to make a new version. I've made several quilts that were "first versions" to learn and try techniques, and I prefer to finish them and give them away so I don't waste the fabric. But I know when making them that they are a learning experience.
I've already made two complete "Affairs of the Heart" quilts and have 12 blocks for another (need to put them together) and now I'm planning on doing a fourth. Each one has used different techniques for the applique and embroidery. And they all look quite different when finished.