The cable cast-on is one of those techniques that you probably have seen used in lots of patterns, but you may not know why! One of the main reasons to use this type of cast-on is that it allows you to cast-on in the middle of your work (i.e, it’s a cast-on that can be used not just at the initial start of a project). I often use it in 2 different places in a project:
Cable cast-on at the beginning of a row:
Here are some examples of where I have cable cast-on at the beginning of a row in some of my designs (Stevie sweater and Jessie’s Girl Top)
Stevie sweater 
Jessie’s Girl Top
Cable cast-on in the middle of a row:
The biggest difference when using the cable cast-on in the middle of a row (vs at the beginning) is that you have to turn the work before you work it (so that the working yarn is coming from the left needle). Other than that, the technique is the same. Here are examples of my work where I cable cast-on in the middle of a row (at underarm of Coffee Bean Cardigan, at armhole opening of Brooklin vest, and thumbhole opening of Study Buddy Mitts):
Coffee Bean Cardigan 
Brooklin Vest 
Study Buddy Mitts
Watch my video tutorial
Ready to learn how to work the cable cast-on? Check out my video below!