Using junk jeans is a hobby of mine. I'll turn them into place mats, potholders, doll clothes, blankets, and now into clothes for me.
I chose an older pattern that had no darts, Simplicity 8426. Then I gathered up my pile of blue jean legs.
This picture of the unfinished jacket back gives you an idea of how I put the jeans legs together higgledy piggledy. I made a piece big enough for each of the two front pieces of the pattern and then started stitching legs together to have a piece large enough to cut on the fold for the back. I used jeans legs that had been opened up at the inseam for the sleeves. (The right sleeve is not in this picture.) That's the only place I left on the original blue jean seam.
Here's a shot of the front. Again, no rhyme or reason for the positioning of the fabric. I just kept adding pieces till it was big enough to cut what I needed to cut. You can see the pockets on the front in this picture.
I found some gray bias tape in my goody box and decided to use that rather than more denim for the front facing. The layers of denim get very thick, and this bias tape did the job just fine. Here's how the front looks from the inside.
And the pockets! I got the handy dandy seam ripper and took pockets off the back of a couple pair of jeans. I was able to salvage two. The placement is as shown on the pattern. I did not line the pockets.
Here's a side view and you can see how the sleeve has the original side seam in it.
I need to add the second sleeve and hem the cardigan and the sleeves. I took great care not to stretch the fabrics too much so that there wouldn't be puckers. Denim is a bear to work with, but I think this is going to be a cardigan that gets worn a lot! I'll add more photos when it's done. It looks better on me than the dress form!