I've been reading a lot about SD cards.
And many that have failed reported that they have been 'frequently' taking the card in and out of the slots, between card readers, cameras etc.
*Shrugs* about what is their definition of 'frequently', but I personally do it maybe once every 2-3 days perhaps.
Maybe need someone to do a 'robust' in-out of slot endurance test and see if it dies
