Swatching is something you either love or hate and I have to admit I belong to the latter group. But no matter how I dislike it, it's something I have to do, at least now and then. And even when I swatch, I tend to cast on around the amount of stitches I assume 4 inches will be and then knit a bit over 2 inches, wash the swatch underneath the kitchen tab, put in between towels, hop on it and dry it with my blow drier. And then unravel it. Sounds awfully professional, right? This mistreating the knitted swatch does have a purpose thought, it tells me how much the yarn can withstand bad treatment. All Nordic Yarns have been happy campers after the blocking episode. Some swatches (and a hat or two) have even had a little trip to drier on low heat, but this is something I do not recommend you to do, as driers vary a lot and the result might be a disaster.
Thankfully when you knit a lot, you kind of know what you're doing and it's not mega crucial to knit a large swatch. And as many of you know, swatches do lie, especially when knitting a larger item like jumper or shawl. Because of this, when I'm uncertain how the yarn will behave when knitting a jumper or cardigan, I block it while it's on the needles just before sleeve separation to see if the fit will be ok. With shawls and wraps I don't find this necessary as you can affect the size quite a bit while blocking the finished item.
Knitting flat vs. in the round quite often gives you a different gauge and the circumference of the item when knitting in the round also might affect the gauge - at least I knit tighter with small circumference like sleeves. To compensate the gauge difference, I tend to go up with the needle size for sleeves. Knitting a simple baby hat can also be a good sample, if you don't have any babies to gift it I'm sure there are charities close to you who would be happy to receive it.
Because this blog post needed a picture, I had to call Tuuli, Nordic Yarn's another designer to help out, she does things properly and knits a lot of swatches, as you can see from the picture, those swatches are just a fraction of her vast swatch stash!
There are tons of advice for how to swatch, but I recommend you to find the way that suits you and keeps knitting enjoyable. There might be some mishaps along the way, but you can always frog. Or not, but that's another story. Anyways, hope you're enjoying the summer and knitting!