USB pen or stick is popular removable storage media. They will wear out with time. USB flash drives may develop bad sectors. Sometimes you buy a brand-new pen drive and find out it is not working. This page explains how to check the health status of a USB stick in Linux and obtain the status to know if it is beyond repair. See

https://www.cyberciti.biz/faq/linux-check-the-physical-health-of-a-usb-stick-flash-drive/ for more info.