Blocking helps with a number of things: the pieces lie flatter, which makes seaming easier. It takes care of any shrinking or stretching that might take place, so that you don't end up with puckery seams. (You prewash fabric before you sew it up, don't you? Same deal with knitted fabric.) It also makes the fabric smoother and more even, and therefore prettier - even more to be proud of.
And it helps in other ways...
I was waffling on what size to knit when I started this cardigan, and didn't have access to a sample to try on. I cast on for the XS, being a little sort of person. It sat for a while, and last October, at Rhinebeck, I got a chance to try someone's on.... it fit perfectly, and then naturally, the wearer broke the news to me that it was the size larger than I was knitting.
This is where blocking really becomes miraculous: there's about an inch and a half difference between the XS and the S, and I was easily able to stretch the pieces to the dimensions of the S. (It helps that the yarn I chose might be slightly heavier than called for in the pattern.)
Yes, those with keen eyes may recognize this as the legendary Must Have Cardigan. I am a sucker for a good cabled sweater, and this one is an excellent example of the form.
I am working it in Galway, which at various times in history has claimed to be an aran, but in my experience has always been a worsted. The swatch was, after washing, somewhere in between...
I cast on for it years ago - around the time Steph was knitting hers - and it's been resting in my stash with only part of the back complete. I picked it up again this fall, after seeing the one at Rhinebeck, and I've been quietly working on it, between design projects. Just today I finished up the fronts, so that all the body pieces are done. To break up the finishing work some (consider this your bonus tip! for the day), I've finished up the body pieces and will sew the shoulders and work the button- and buttonhole bands now, before working the sleeves. This will give me a chance to assess how long I want the sleeves to be, as I'll be able to put the body on, figure out where the sleeves will hit my shoulders and measure down from there. Clever, eh?