1) I have ~7 cards (all from China and Sandisk, solely because Sandisk has a website where you can verify the card is genuine) that are in daily 24/7 use for 6-

1) I have ~7 cards (all from China and Sandisk, solely because Sandisk has a website where you can verify the card is genuine) that are in daily 24/7 use for 6-8 years with no issues (mounted in rw mode) 2) ... 4) that's true for any storage media If you ever tried running uSD card in SDR104 mode, you'd notice that they tend to heat up way more than in lower speed interface modes. So for longetivity, I guess it's better to run them at HS mode (which is just 50MHz), or at least lower the SDR104 bus frequency from 200MHz to something lower.