It's been around for quite some time, but no worries. I just brought it up as an idea for how you might have been able to tell. I think Linux in general is just busy writing away to the disk (in this case, the SD card is the hard disk), and SD cards having a limited number of write cycles (even with wear leveling) can burn out.
If you search on the Raspberry Pi forum you can find plenty of discussion about this, and potential steps to take to reduce writes/extend life -- this is an old one but a good discussion: https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=20505
I suspect there are SD card models which have a better life in this regard than others as well.