answer:Nearly every invention is useless until you have a need for it. If you never broke your hand by wrapping a dog’s leash around it, why would you want a retractable one? However, if you have very weak hands, like I do, the retractable leash is the only thing that makes it possible for me to take my dog for a walk. If you never called anyone, why on earth was the telephone invented? If you never needed seat belts, what a waste of money they are – except for the hundreds of people whose life have been saved by them.