Whenever you unplug a USB device from its connection, make sure you are careful in doing so. The best way to unplug a device is by pulling firmly straight out of the connector. Wiggling the USB connector or pulling from an angle can cause the plug to bend or can damage (and break) the internal connectors which make the device work.

This tip was prompted by having a friend bring a broken USB flash drive to me in order to see if I could do anything about it. Upon inspection, the small metal strip connectors were broken. When I asked them to show me how they remove the device, they both wiggled and pulled at an angle (quite violently).