I recently learned that one of my quilting friends always uses bias binding on her quilts. Now I know that you must use binding whenever you are binding a curved edge, but I wondered why go to the trouble of making bias binding for straight edges? And don't you use more fabric for a bias binding? My friend told me that she was told that bias binding lasts longer than straight binding. Being a "research-a-holic" (is that even a word?), I went to the internet and researched bias vs straight bindings. To my surprise, I found out a couple of things.
1. Bias binding does wear better than straight binding. This is because the bias has stretch and flow and moves at the edge. Straight binding has only a couple of threads at the very edge and will wear out faster. So if your quilt will get lots of use, the bias binding may be the way to go. If you are doing a wallhanging, straight binding should serve you well unless you have curved edges.
2. Bias binding does not require more fabric. It takes the same number of square inches of fabric for both types of binding. It seems to take more for bias because you are cutting straight strips across the width of the fabric for straight binding while bias strips are cut out of a square.
Whichever method you use, I encourage you to use a folded binding rather than flat. Folded binding is when you cut a strip of fabric (usually 2 1/4" - 2 1/2") and then fold it in half lengthwise, sew it to the front of your quilt matching the raw edges of your quilt and raw edges of the binding, then fold the binding over to the back of the quilt and hand stitch. This gives you a double layer of fabric for your binding. Flat binding is only a single layer and really won't last long.