I would suggest installing the Intel Toolbox. The only way of determining if the SSD has reached it's end of life is through the smart attributes. E9 looks like the field that would need to be monitored. The toolbox user guide says this:
" This attribute reports the number of cycles the NAND media has experienced. The normalized value declines linearly from 100 to 1 as the average erase cycle count increases from 0 to the maximum rated cycles. Once the nomalized value reaches 1, the number will not decrease, although it is likely that significant additional wear can be put on the use. Use the Normalized value for this attribute."
The maximum space of your drive is not an indicator of drive wear.