Mechanical "Wear and tear" describes the gradual deterioration or normal use inserting and ejecting the SD card or damage that occurs physically
over time. Mechanical wear naturally occurs in individual machine parts of the locking mechanism for a number of reasons, like the environment the SD card is stored in, temperature, expansion and contraction at different rates over time because of different compositions of alloys.
If left alone perpendicular with respect to your dresser table the locking mechanism would survive for years and the SD card would become obsolete!
If you don't use it .You're going to lose it.
-DP