The first thing any experienced knitter will tell a novice is not to underestimate the importance of gauge. "A gauge swatch will tell you if your knitting will end up too big, too small or just right." Ah yes, the Goldilocks approach to knitting.
But I'm more of a fly the the seat of your pants kind of knitter. A knitter who says, "to hell with your gauge swatches!" I am now also a knitter whose fabulous mohair sweater will probably be too small.
The more careful crafters are tsk-tsking away now. What's that carpentry saying -- "measure twice, cut once"? Not quite the same thing, but the sentiment is the same: more prep time equals less mistakes.
Ok, to be completely fair to myself, I did measure my gauge. I even took it in the round, since this sweater is done in the round (whether this is truly necessary, I'm not quite sure -- I've seen arguments both ways). However, what I didn't take into consideration is that I would change my entire method of knitting after I took the gauge. Remember my epiphany about combination knitting? It was like a lightening bolt and my knitting is so much faster. However, my knitting is now also tighter. Whereas my gauge was initially correct at 10 1/2 rows and 14 stitches to 4", my current gauge (which I didn't bother to check until I was ready to separate for front & back) is now closer to 12 rows and 16 stitches. Which leaves me 5 inches short on the body of my sweater.
What to do? I am not an advocate of frogging, and especially not when it's mohair. The sweater was meant to be big, so hopefully it will just be a bit more snug than intended. I'm still working it, and when I get to the sleeves and cowl neck, I'll use bigger needles to get the correct gauge. If it's too small, it will be a Christmas present (although a part of me will cry inside).
So, what's the lesson of the day? If you want to try a new method of knitting, don't start it in the middle of a project. And if you must, then check your gauge.