I remember a few years ago there was a trend for turning old jeans into denim skirts. But they always had raw edges, and looked just a bit like skirt versions of cut off jean shorts.
Inevitably, though, we have old jeans. I have stack of them: ones I've gone through the knees of (or the bottom of), ones that have faded too much, or been trodden down at the heel, ones that people have given me to make stuff out of. So what to do with them all? Well, denim skirts, obviously.
You cut the legs off to the length you roughly want, unpick the inside leg seam, patch them over and sew the front pieces together, and the back pieces. I put in a little triangle from the back of the thigh so it's not too short or tight.
Then, to stop it having a raw edge, sew bias tape around the bottom. I did one in navy for a colour averse friend, and ones in orange and dark red for me. All in all, less than an hours work for a new skirt. Result.