I usally don't worry about dye lots. Nowadays with the technology, the yarn is always the same color or the difference is not noticeable. I ordered one extra ball of Brilla for my top and when it arrived I was so disappointed. Look how different the shade is:
The ball on the top is the new ball. Not only the dye lot is different but this yarns have a complete different label design:
This is how much I was able to knit with one ball. I hope that if I am lucky I won't even need the additional ball, but if I do, I might try the trick of knitting with two balls alternating the dye lot to blend the colors in. I don't know, we will see. So far, Brilla seems to be discontinued. This ball was really hard to find, so I am not even going to try to find the same dye lot. I will see what I can do with what I have.