I normally use the knit bind off method at the end of my knitting projects, but binding off cables is a little different. In this video, I demonstrate how I go about it.
Whether you knit or purl as you bind off is not important; the important bit is that you decrease (using k2togs or p2togs) as you bind off the cable stitches.
The reason for this is that the act of cabling crosses stitches over each other, which makes the knitting in that area compact and narrower. If you bound off all of these stitches the same as you would for stockinette or another flat stitch, the bound off edge would flare out to be wider than the rest of your knitting.
In this particular example, I work 9 single decreases across the 18-stitch cable width.
I hope this tutorial helps you :)
