I thought i already accounted for that by stating "most users will get a decade of use". That's roughly 66% of linear degradation to 0%.
> and that by the time it is at least 90% on a 256gb or even 512gb SSD it will be effectivly unusable.
As i understand it, the "lifetime" is a reflection of the spare sectors, meaning once the spare sectors run out you'll start seeing errors instead of relocated sectors. It will probably continue for some time after that.
Knowing Apple, if it becomes a problem anytime within the first 5-6 years, they'll replace it for free. I had a 2008 iMac with a manufacturing problem on the Seagate 1TB drive it shipped with, and 5 years after purchase (2013), i was able to get the drive replaced for free despite my machine showing no signs of the error. 5 years after purchase, and a full 3 years after most consumer laws stop protecting you.
Other than that, the only reason this is a "problem" is because SSDs has an indicator that tells you when they'll expire. Spinning rust doesn't have that, but some spinning rust will also expire after 5-6 years, and most will have expired by the time a decade has passed (assuming daily usage).
