I'm a big advocate of doing gauge swatches before launching on a project that makes a point of them. Which is most every project! Certainly it's needed for sweaters, socks, mitts, skirts... all things that need to fit well.
This is the step that most new or inexperienced knitters and crocheters skip. This is the step that even experienced knitters/crocheters skip. This is a step that I used to skip.
For most of us, we don't have teachers or knitting mentors who help us understand why gauge is important. So we think it's just one of those extra, aka optional, steps that stand in the way of our jumping in to our new, exciting project with both feet.
But, sooner or later, there comes a moment when we sense that there is something important about that whole gauge thing. Sometimes, it's when we work on a sock using the needles and yarn called for in the pattern and realize about 1/2 way to the heel that the sock could fit an earthworm. Or, it could be when we knit a sweater, all the while thinking something may be off with the size, but convince ourselves that it will all be well in the end. And it never is.
At that light bulb moment, we ask the question, "What is Gauge, Really?" and become advocates of doing gauge swatches. And, for the most part, garments fit, stitches look as they should, yarn requirements work out and we become much more confident knitters and crocheters.
But note I said "for the most part".
Because recently, I've had several people with projects where gauge just didn't yield all the right answers. It's left us scratching our heads trying to figure out why and the differences. And then, as luck would have it, it happened to me... IS happening to me on my current project.
I'm knitting the Cameo Shawl. It's knit mostly in garter stitch and uses 2 colors across 3 sections. The first section is all color A, the second is colors A & B, and the third is all color B. The pattern calls for 2 400-yd balls of fingering weight yarn and the gauge is 18 stitches over 4inches, after blocking. I picked my yarn, did my swatch, got my gauge and off I went. I love how the stitches look. I've loved knitting on this shawl.
But then something happened as I finished the first section, all color A. I was running out of color A yarn. How could that be?? So I did what we all do... I blamed the yarn. The ball must not have had the correct yardage. And it couldn't have, because why else would I be running out? Ok, get over it and buy another ball. Which is what I did and carried on. At the end of nearly every couple of rows, I'd stop and admire it and smile as I love the way it's looking, love the yarn, love the stitches. I finish section 2.
Then, again, there's a problem as I get to section 3. The shawl is beginning to look very large. I mean, LARGE compared to the original photos. I check the finished dimensions from the pattern and see that mine is, in fact, very large. And now I'm becoming increasingly perplexed. I'm reminded of a similar situation with a friend working on a different shawl.
Now, as a designer, I strive to write patterns that represent my designs as completely and clearly as possible, and after a test knit or two or three, am confident that all the needed info is there. So I assumed no less with Cameo and my friend's pattern, both written by accomplished designers. And we were not disappointed. All the information was there to proceed, clear as water, specific, exact.
So what's happening? Well, all of the projects in question were done mostly in garter stitch. As best as I can tell, it has to do with the designer's interpretation of gauge after blocking. Garter stitch is extremely stretchy. Just lay it flat to dry and you have one answer, block it out with the stretch and you have a completely different result. With my shawl, laying flat to dry, it has the perfect gauge of 18 stitches over 4". But stretch it out and it's as low as 12 stitches over 4". That would account for the differences in yarn requirements and shawl size. I don't want to believe it, but there are no other viable explanations.
So, hear me out! Gauge is Important. You want to test for it, get it right. BUT, do what you can to get a sense of the designer's assumptions regarding the blocking of the piece before doing the measurements. Because BLOCKING MATTERS, too! Especially when it's garter stitch...