Micro SD keep failing?

I have numerous Micro SD cards, last count 18. I keep buying them as they keep failing!

Class 10 and a couple of U3. To date only one U3 has failed but 11 of the others are no longer reading on my PC, because some are I have to question what is going on here? Surely I cant have 11 faulty Micro cards?

Some look like they will open them stop opening and the folder is gone?