When you start to design, you end up with lots of swatches. The only way to really answer the question, “What will this pattern look like in this yarn?” is to swatch. And the only way to make a good guess at how many stitches and rows you need to get to the size garment you want is to swatch some more and measure and count stitches and do the math.
Well, then you end up with a lot of swatches. Some that worked, some that didn’t, some that look great but not in the project for which they were intended.
I keep my swatches in binders with the notes I used to make them together in sheet protectors. I also file away rough drafts of patterns, graph paper filled with full sized layouts of shawls, and failed ideas.
Since I design only four or five patterns a year, I’ve only got about three of these binders filled right now. I mostly work in fingering and lace weight yarns so the swatches aren’t very thick. And I’ve found them useful as a reference and inspiration for new ideas.