SSD's life is measured in TBW - terabytes written (reads don't count); with a 256 usually having a rating of 70* or so TBW. To hit that, you'd need to write about 190GB per day for a year; i.e. fill 2/3 of the disk every day. At 10 GBs/day, you would get 20 years of life. I suspect most users are no where near 10GBs/day, let alone 190GB/s per day, every day; so SSD life is a non-issue. By the time it fails you're likely to be way past when newer OS versions no longer work.
* That is likely conservative, given manufacturers build in extra capacity to allow for wear as well as to ensure warranty claims are not so high they impact profits; i.e no one expects a computer to die after 1 year or a car after 5years/50k, despite the length of the warranty.
