Using your ChiaoGoo End Stoppers is super easy. When you want to switch needle sizes between projects, just grab the appropriate stopper according to the cable code. For example, if you have an [S] coded cable, use the white small [S] stopper. Then, screw the stopper into the end of the cable. This will hold your current project in place while you can use the needle tips for a new project. Remember to keep track of which color corresponds to which size so you can quickly find the right stopper. As for maintenance, simply keep them in a dry place when not in use. Avoid exposing them to excessive heat or moisture, which could potentially damage them. With proper use and care, your ChiaoGoo End Stoppers will last you a long time.