I ran out of yarn three rows before starting the border around the collar on my little Aran Coat:
I saw that I was running out when I started the collar. But the thing is, I had no idea what shape the collar was going to be, nor the size of it. The pictures in the book didn't show it, nor did the schematic diagram show the collar. Upon reading the directions, though, it was clear that the collar was a sizeable piece of intricate knitting, so I went ahead and ordered another skein of yarn. I hope that WEBS still has the dye lot, but if they don't, oh well -- it will just mean that the border around the collar and the button bands will be a slightly different shade of purple!
I usually order an extra skein of yarn when ordering a sweater amount, but for some reason I didn't this time, and it bit me in the ass. Lesson learned! Even though you think you know what you are doing (I mean, I used a calculator and everything), always order extra yarn! The bonus is, I'll have purple for my scrappy hats! Yay! My purple yarn should be here today or tomorrow.