The ratio of the total amount written to the capacity is 625:1. For many purposes that will be fine, provided that the wear levelling works. I would suspect that it will see out the lifetime of most notebooks on moderate usage. Fitted with a 128GB drive, this implies a lifetime write allowance of 80TB. If the notebook lasts 5 years, then that's 44GB per day used 365 days per year. Of course many notebooks won't be used that frequently or consistently,.
However, it the 625:1 the full story here? Flash memory is written out in large pages and a relatively small 4KB write can involve the controller writing out a very large page - maybe 128KB or more, depending on the page size of the memory. Controller optimisation with write caches and so on can reduce that overhead by "rolling up" writes into a few, larger ones. However, the issue here is does the 625:1 ratio apply at the back end (what the controller writes to cache) or the front end (what the computer writes to the drive)? If your "write allowance" is rapidly used up by many small writes (quite a common thing when managing file systems), then the drives might fail rather faster than the specifications would indicate.