Does fstrim wear out SSD

fstrim does not wear out your ssd; on the contrary, it increases its lifespan. The writes reported in lifetime_write_kbytes refer to file system writes at a higher abstraction level and don't necessarily correspond to physical writes to the drive. So although there are 40 TB of writes reported in lifetime_write_kbytes, running $sudo smartctl -s on /dev/sda7 followed by $sudo smartctl -a /dev/sda7 reveals that I have only written 750,000,000 blocks of 512 bytes each, which comes out to 375GB, which is a more reasonable value for two months of use.