Most spinners and spinning books will tell of the wisdom of planning and sampling to help you make the yarn you want. This is smart because it’s frustrating to end up with a yarn that’s the wrong thickness for the project you hope to make or that isn’t nearly enough yardage. So don’t spin like me.
Occasionally I do follow that genuinely good advice, make a few yarn samples, and figure out if I have enough fiber to make the item I want to knit. Mostly though, I spin just to do it. As an advanced beginner or maybe an intermediate spinner on a good day, I can spin well enough to make a continuous yarn. So I let my mind go and spin. Whatever. Last night I set up my Lazy Kate with three previously-spun bobbins (one of burgundy-colored Icelandic, one of gray Shetland, and one of assorted colors and wools), put a bulky bobbin on my Louet, and started plying. I tension the strands through my fingers and watch the colors twist around each other. I filled my bobbin crazy full, and because sometimes fortune favors the foolish, got away with it.