The question of how many knitting needles do you actually need is really about opinion. While you obviously need a pair of needles for one project, it is suggested that you start with two or three sizes to discover which size is best for you while you learn. Once you get past the beginning stages, you will need different sizes of needles for different projects. This is why it is highly suggested that you invest in a high-quality kit that includes eight or nine different sizes. Finally, if you are working on numerous projects, you will need a set of needles for each project.