Since it wasn't immediately clear to me how the percentages were pulled from the smartctl output, I'll note that "Perc_Rated_Life_Used" is the relevant readout.

Since it wasn't immediately clear to me how the percentages were pulled from the smartctl output, I'll note that "Perc_Rated_Life_Used" is the relevant readout. (Some online sources mention "Wear_Leveling_Count", and even misreport that as a percentage – but in fact that seems to be an absolute count of the number of times each single block has been rewritten. The percentage is presumably this Wear_Leveling_Count divided by the rated number of cycles.)