I only bought 3 skeins of Lion and Lamb, and bought them a year ago. Since then, I've read several places that three skeins are not enough. So, I thought I'd preempt the problem and measure the weight of the ball of the L+L as I progressed, figuring that:
Sections 1+2 should account for 20% of the total yarn
Section 3 should account for 60% of the total yarn
Sections 4+5 should account for 20% of the total yarn
So this means of a total of 300 grams of L+L, 60 grams should be spent on each of the 'end' sections and the rest go in the middle.
So, as I knit section 2, at the end of every 12 row repeat I measured how much was left in the ball (we have a tiny scale for weighing our bird, which does grams and ounced). After 5 repeats, i had 50 grams left on the ball (so I'd knit 50 grams). At that point, I did the first 6 rows of the repeat and then moved on to section 3.
So, there you go.
Nerd mode off.
Here's a pretty sock that I"m doing too (Schaeffer Anne, a lovely yarn) just to balance the nerdiness with some beauty.