Intel claims their SSD to have 5 year lifespan
 

Intel’s claim of 100 GB/day for five years totals approximately 182500 GB worth of writes or 182.5 terabytes. Let’s make a big assumption that we can max out the 70 MB/sec max transfer rate until the SSD dies, this gives us 19 minutes to write the entire 80 GB disk and 30 days to hit 182.5 terabytes. Now I don’t know about you, but that doesn’t look too shabby considering most people would notice something bad was happening after an hour or two, let alone 30 days.

Paquin tells us that engineers in the Intel labs have actually completely worn out an SSD, but unlike regular hard drives that fail catastrophically (gotta love that thunk or high-pitched whine of a head crash), you probably won’t know if your SSD is actually failing. Flash memory has a limited number of write and erase cycles, but modern SSDs perform wear leveling which spreads out the writes throughout the disk. Essentially the drive wears uniformly and without the user knowing any better. If some blocks are getting close to being worn out, the drive controller rewrites the data to spare blocks and then remaps the logical address to the new location, so basically your operating system doesn’t know any better. In fact, modern SSDs contain extra capacity just for this purpose.

http://www.tgdaily.com/content/view/39204/135/