Counter-intuitively, the "micro" size is the most durable from the point of designed insertion lifetime. The standard and mini connectors were designed for less than daily connections, with a design lifetime of 1,500 insertion-removal cycles. (Improved mini-B connectors have reached 5,000-cycle lifetimes.) Micro connectors were designed with frequent charging of portable devices in mind; not only is design lifetime of the connector improved to 10,000 cycles, but it was also redesigned to place the flexible contacts, which wear out sooner, on the easily replaced cable, while the more durable rigid contacts are located in the micro-USB receptacles. Likewise, the springy part of the retention mechanism (parts that provide required gripping force) were also moved into plugs on the cable side. COUNT 4
QSN1 What size is the most durable from the point of designed insertion lifetime? ANS1 the "micro" size QSN2 What was designed for less daily connections? ANS2 The standard and mini connectors QSN3 What has reached 5,000-cycle lifetimes? ANS3 Improved mini-B connectors QSN4 What was designed with frequent charging of portable devices in mind? ANS4 Micro connectors