Yoyo strings wear out and break. It's part of yoyoing. Don't yoyo with a worn or dirty string, because you might send your yoyo flying! You should always have at least 25 replacement strings on hand so that you can switch to a new, clean string before the old one breaks. Clean, new strings work better. Ask any yoyo pro!
New to yoyoing? Don't miss our educational Yoyo Buyer's Guide.