I often read comments like; “used CF cards for more than 10 years and never had a failure”. Unfortunately if you have a closer look at the technology for memory today, you would quickly come to the conclusion that the older technology was more reliable than it is today, and why is that so?
The frequency of card failures is increasing and the reason is that Consumer Grade Memory is no longer as robust as you would hope or expect.
Manufacturers of consumer grade memory have been on a quest to increase capacity, reduce cost and increase speed. One thing they have done is shrink the geometries, from 40nm down to 19nm, and next is 15nm (changes about every 18months). So by example a CF card today, using MLC NAND Flash only has a write endurance spec of < 3,000 writes. When it goes to 15nm, endurance write will be down to 2,000. Now if you purchased a cheap card, very likely it is TLC Flash and only has < 1,000 writes.
With smaller geometries there are many downsides which requires modifying of firmware and circuitry. The manufacturers are not open about the endurance write spec on their products. However they comfort you with an offer of Lifetime Warranties, and for a product that has a Limited Life. Small comfort when you lose 100s of photos on shoot, who cares about the replacement card – where are my valuable images! NAND Flash has a limited number of writes and ultimately will fail with extended use.
Only advice I can give is look at Industrial Grade Products which use SLC NAND Flash. These products have Endurance Write Specs >2 million. They cost more, but extremely reliable, slower performance, but not an issue for the majority of serious photographers.