No new yarn will be assimilated.
I frogged the Cardigan for Arwen. It is a lovely pattern, and I surely will get around to making it one of these days. I liked the yarn, too (KnitPicks Andean Silk in Cornflower), but after I blocked the back (ages ago, mind you) and realized it blocked out way bigger than the size I was making, I knew I was courting, if not outright disaster, than at least a really humongous sweater.
No, I didn't swatch. I cast on 20 or so stitches, did a few rows, and measured that. I didn't block the swatchlet, because I pulled the thing out and cast on the back.
In thinking of what I would do with the yarn (because, y'know, I don't have enough WIPs...), it occured to me that I could make EZ's Surprise Jacket (adult version), but wouldn't it be more fun with some other colors of Andean Silk for stripes? Off I go to the KnitPicks website, to check out the other colors. And, miracle! I didn't buy any. Even I couldn't stretch the "to finish a WIP" rule to cover additional yarn for a project that was not truly in progress, and indeed, I might not actually follow through with. Also, I didn't think any of the other colors went that well with the Cornflower.
I want to do the Surprise Jacket in a hand-dyed multi anyway. From stash.