OK I admit it, when I was a new knitter, I hated to knit swatches.
And Yes, I know (heard tell) Swatches LIE. --which is not quite true, swatches always tell a portion of truth.. (the lie by omission, rather than commission)
As I got older, I came to love knitting swatches.
Not that I always swatches for a project I was about to knit, but just swatches.
Knitting swatches just for swatching sake still teach you things.
You can learn to read patterns.
Or learn new techniques.
You can experiment with edges. (there are edges besides the ubiquitous chain stitch for the selvage!)
Or practice different cast ons.
You can learn about the properties of a type of yarn (wool or linen, or cotton, or what ever).
Or practice with a specific yarn, until you understand how to work with it.
You can do stuff you know, like garter stitch, or ribbing, or stocking knit stitch.
Or you can learn stuff about how these stitches interact.
You can call these bits of practice knitting swatches.
Or you can call them wash clothes (I never knit dish clothes.. only wash clothes)
Take cast on's...
I Love a tubular cast on...
BUT look here—you'll see why it is a great edge when followed by 1 X 1 Ribbing, and only so-so when followed by stocking knit.
In sprong-ee wool, a channel island cast on is a delightful tight picot.
In soy silk (a semi natural vegetable fiber) or in other vegetable fibers, it's much less impressive,( but still quite nice.)
Knitter often look for matching cast on/bind off methods..
and over look I-Cord –or a tubular cast on, and matching tubular bind off.
Why learn these techniques on a special project? Learn on a swatch!
There are dozens of 'experts' who push the idea of a chain stitch for a selvage everything.
There are lots of selvages “stitches” --I-cord is often over looked –and more overlooked is simple double knitting.
Both of these techniques are ways to “knit in the round” while working with straight needles.
In theory, they are identical. (they both create 'tubes' of knitting)
In reality, they knit up very different..
I-cord makes a curved edge, (it rounds over), simple double knitting makes a very flat edge.
And while everyone knows (or should know!) stocking knit curls, Cables don't!
(think it's a trick of the fiber? See the same edging here, or here.(felted)
Cables are an underutilized edge treatment--all too often they are bordered by garter or other edges.. Why?
Why not just use a cable edge to a garter stitch scarf --rather than a garter stitch edge to cabled scarf?
Or just really get (grok!) how knits and purls interact.
When you set up knits and purls in vertical columns, the KNIT are most prominent. (think of ribbing)
But when you set up knits and purls in horizontal rows, the purls are most prominent (think of garter stitch)
You knew that.. but did you ever really think about it?
Or swatch and analyze it?
When if you switch from ribbing to garter, or from stocking knit to garter or from stocking knit to reverse stocking knit or to seed or to (–a host of other knit and purl patterns), these characteristic are going to be part and parcel of the designs!
Persnickitiness in the details make simple stuff, Excellent.
And why not learn the detail with a swatch? Even if you call the swatch a wash cloth?