Having just returned from the fourth ride of the season, it’s worthwhile to note how the MicroSD cards in the cameras are doing.
The Sony HDR-AS30V helmet camera has been running a 64 GB Sandisk high-endurance video-rated card since late August 2017:
In those 29 calendar months (maybe 20 riding months) I’ve ridden 4500-ish miles at perhaps 12 mph, so call it 375 hr = 22.5 k min. The camera fills a 4 GB file every 22.75 min, so it’s recorded 1000 files = 4 TB, which is 62× its capacity. This is better than the defunct Sandisk Extreme Pro card (3 TB & 50×) and much much better than the Sony cards (1 TB & 15×), although I have caught the camera in RCVR mode maybe twice, which means the card or camera occasionally coughs and reformats itself.
The Cycliq Fly6 rear camera uses a Sandisk 32 GB card that’s been running flawlessly since late 2017:
The new 16850 lithium cell continues to work fine, too.
The SJCam M20 rear camera also uses a Sandisk 32 GB high-endurance card and has worked fine since early 2018. An external battery eliminated all the hassle of its feeble internal batteries, although the one that’s been in there has faded to the point of just barely keeping the clock ticking over during winter weeks without rides:
All in all, paying the premium for video-rated MicroSD cards has been worthwhile!
The Smell of Molten Projects in the Morning 
Where do you get your cards ?
I’ve had bad luck with ebay and have had a little better luck with Walmart and Best Buy. I’m about to deploy three Raspberry Pi boards and would like to find a reliable source of good cards.
The Sandisk video-rated cards came from Amazon, but with amazon.com as the seller. Their commingled inventory is a real problem, but for oddball parts I think it’s survivable.
Samsung cards come from samsung.com at essentially the same price as from Amazon, but with assurance they’re not counterfeit crap.
Apparently Samsung’s “Evo Select” is Amazon’s known-good brand (“Shop Samsung Authentic” and “shipped from and sold by amazon.com”), so it’s probably good, although it seems less expensive direct from Samsung.
https://www.windowscentral.com/whats-difference-between-samsung-evo-select-and-evo-plus
If the Evo Select cards die horribly, I’ll tuck video-rated cards in the RPi slots and see what happens.
Anything from eBay is guaranteed to be counterfeit.