I‘m going to be knitting a sweater in the future with the Caron x Pantone bamboo yarn. It is color dependent, and I can’t buy anymore yarn because it’s discontinued! I’m surely going to check my gauge, but I also have to make test swatches?? I only bought the yarn they required in the pattern. Could it be that I’ll end up with not enough yarn, regardless of the precautions I take? I’m a bit pessimistic about starting the sweater now
It is possible you’ll end up with too little yarn, but it it’s also possible you’ll have some left. Remember the amount of yarn is determined by the designers gauge so it’s always a good idea to buy an extra skein. You could check Ravelry stashes to see if anyone has some in same yarn, color and dye lot if it has one.
That said …yes a gauge swatch is important especially for a garment. You can make it and count and then rip it out if you need that yarn later.