If the read speed had degraded, I didn't notice since the RAID controller is the bottleneck in this particular system. We burned out the drives with a 800Mb/s

If the read speed had degraded, I didn't notice since the RAID controller is the bottleneck in this particular system. We burned out the drives with a 800Mb/s sustained 24/7 write stream. In post-mortem I did the math and the consumer drives ran out of endurance in less than a month. We replaced the drives with enterprise drives which were expected to last at least 3 years. Also, here's a really strange finding... TRIM doesn't matter as much as one would expect. Many TRIM implementations are buggy. If the SSD contains a reliable TRIM implementation, then you can 100% guarantee that it will also have internal "move stable bits around to level out the usage" code.