Watching wool dry.
I got to a point in the Lace Trimmed Denim Sweater where I had to knit to "x # of inches" before doing the underarm decreases. Normally I'd just keep knitting until I reached that measurement. BUT, to improve the look and drape of the handspun I've been knitting the pieces slightly smaller and blocking them to size. When asked to knit to a certain length, I could go by the rows per inch measurement --- but that isn't necessarily the same over the lace portion as it is over the main, stockinette section. Soooooo, I'm blocking what I've knit so far to the correct width, measuring the length so far, and then doing a calculation based on rows per inch over stockinette to figure out how many rows to knit before doing the underarm shaping.
Which leaves me watching wool dry.