Distress hits when knitting a project and running out of the same dye lot in midstream! Knowing ahead of time that your perfect yarn is short on yardage also challenges knitters.
There are two major ways to use a different dye lot without creating an obvious line. In the first, alternate the skeins with different lots every few rows rather than knitting with one skein then the other. This avoids two large blocks of differing color. This technique also works when blending hand-dyed yarns from the same dye lot, which often have a great deal of color variation. A variation of this approach uses a skein until about 50 yards remain, then alternating every few rows to minimize the color join.
The other major method is to use different dye lot skeins strategically. In this method, when knitting a large item such as a sweater, one knits the front of the sweater with one dye lot and the back with another. Utilize the dye lot with the least number of yards for smaller features like cuffs, neck trim or collar. Utilize different dye lots in different stripes also.