Generally you're looking at hundreds of terabytes, if not more than a petabyte in total write capacity before the drive is unusable.
This is for older drives (~6 years old as I said), and I don't know enough about storage technology and where it's come since then to say, but I imagine things probably have not gotten worse.
[0]: https://techreport.com/review/27909/the-ssd-endurance-experi...