Apple should build a system to scan the three-dimensional shape of its customers ears using the iPhone Face ID sensor. They could collate that data and feed it

Apple should build a system to scan the three-dimensional shape of its customers ears using the iPhone Face ID sensor. They could collate that data and feed it into a machine learning algorithm that could come up with two or three alternative AirPod shapes that would suit the widest array of ears. (Then use the same "Ear ID" feature on your iPhone to tell you which model best suits your ears.)