I love cables. Cables are one of the reasons I started knitting in the first place. However, they pose certain challenges. Specifically, they can cause gauge problems.
When you make a cable it twists the fabric, making the gauge of the cable tighter than the rest of the fabric. They also shorten your row gauge, because the stitches in the cable are pulled diagonally.
Where am I going with all of this?
I started a sweater. Most of it is in 2x2 ribbing, with a cable panel in the center front, and maybe along the sleeves when I get that far. I did a gauge swatch with multiple needle sizes and of all of the stitches I planned to use. All seemed well, until I actually started the sweater. The problem was that I chose the needle size that worked best with the ribbing. It's going to make up the bulk of the sweater, right?
After working through the first eight inches of sweater, I discovered that the perfect ribbing gauge was way too tight for the cable pattern, which was coming out very stiff--it could stand up by itself. There was only one thing for it: I tore it all out and started over on a larger needle size.
Bottom line: If you are make a project with a cable pattern, use the gauge that is best for the cable, not the ground pattern.