Using addi Turbo Circular Needles is a piece of cake. First, choose the right needle size for your project according to the yarn you're using. The smooth nickel coating means you can start knitting right away, and the yarn will slide easily over the needles. When joining the needle tips with the cords, make sure the joins are secure to avoid any snags. As for the non - standard sizing, always double - check the actual size before starting your project. For maintenance, keep the needles clean. You can use a soft cloth to wipe them after each use. Avoid dropping the needles, especially the plastic tips of US 36 and US 50, as they may break. Store them in a dry place to prevent rust on the metal parts. With proper use and care, these needles will serve you well for many knitting projects.