Once when doing a binding, I ran out of fabric that was wide enough on the last 12" or so. Once I realized that only half of the width of binding actually shows due to folding, then I knew that I could piece the binding horizontally, putting a completely different fabric on the part that folds to the inside. The binding was slightly thicker in that area, but nobody was the wiser. I thought I was pretty smart, and I saved the project.