#12 Power On Hours
Contains the number of power-on hours of the SSD. This may not include a time that SSD controller was powered and in a Non-Operational Power State (NOPS).
"Power On Hours" parameter in NVMe SSDs only reports the actual working time of the SSD, the time spent on 1/0 operations, etc., and (on most NVMe SSD models) does not include standby time (when the SSD controller is in a sleep state). In such a case, the "Power On Hours" raw value could be relatively small (and much less than computer power-on time) as modern NVMe SSDs are very energy effective and extremely fast.
Important note: do not confuse with the number of power-on hours of the computer, these numbers are completely unrelated.