It's hard to predict without SMART features to measure the current wear state. Write amplification from the file system, and from the drive itself if you're not using large block writes, means you can't just calculate - you have to measure.
To extend on your comment: It's not possible to predict individual drive failure with reasonable accuracy. It's disconcerting to see the parent comment suggesting this still sits at the top of the thread.
You can roughly predict the longest possible lifespan for a SSD under a given workload. Regardless, a significant percentage of drives will still die earlier than that.
I'm only saying this from experience developing storage systems that are yet unreleased. You can predict the lifespan of the SSD in the storage system if you give up many of the functions of the SSD controller and put them in software RAID.
If you're talking about most incredibly naive SSD storage systems available today (excluding violin memory and maybe xtreme/pure), then I agree with you.
I'm sorry, I didn't mean you'd calculate some value once for all the drives. It's definitely something you measure over the lifespan of the SSD itself with the rest of your QoS subsystem.
Reads, program/erases, controller ecc/ read disturb management, the g/p list mapping of the blocks... This all has to be taken into account in a dynamic way. And yes, some people are doing this at a higher level than the SSD controller.
