Question micro sd cards stopped being recognized

[wicked_sticky]

Back in late 2014 i bought a few different sandisk micro sd cards all were tested at the time, the 2 .

I got a phone with a micro sd slot a few months ago so I tried using these cards...
The best of these old cards was a 32gb class 10 card it was initially used for a few weeks then put in its case for 4+ years. This card worked fine in my phone for 3 months, then without warning stopped being seen. No device or pc card reader detects a card present when I pur this micro sd card in it.

Another of these cards was an 8gb class 4 card. This one was a spare, just sat in its case all these years. This card now isnt detected by any device.

1. is this normal behavior for a failed microsd card? no errors, the android and windows just behave like the sd slot is empty?
2. Until Out of dozens to hundreds of cards and usb thumb drives Ive never had one fail without physical damage or me screwing up some partitioning commands. Ive got drives more than twice as old as these that still work. Do micro sd cards go bad from disuse or am I super unlucky?

 

[helpstar]

Are you sure these cards are supported with the phone or the sd card readers?

In which phone was it working initially?

1. yes, could be faulty
2. probably super unlucky