I will let you on a little secret: I do not swatch....I hear gasps and knitters all around the world frantically calling this a sacrilege. That's the truth I do not swatch. I just get started and knit on...
That worked so far because I mainly knitted for my daughter or shawls. The project on my needles right now is a cardigan in fingering yarn and that better fit me well. First I will probably want to wear it as I will not be purchasing any clothes and also because of the amount of time I will spend knitting I do not want any surprises. Which brings me to my first swatch.
I will be making the Madewell Cardigan by Joji Locatelli (purchased in 2015) with some madelinetosh sock in a blue/denim colorway. I didn't keep track of the color, that's usually what happens when you buy yarn and it takes you 3 years to get started on the project.