Glossary
SSD wear
How much of an SSD's rated write endurance has been used, reported by the drive itself.
What it is
Flash storage can be written a large but limited number of times. The drive reports how much of its rated endurance is used as a percentage, along with the total data written.
Normal use takes years to wear an SSD meaningfully. Heavy swap and large builds add up faster.
Why it matters
It is one of the few health figures that matters when buying or selling a used Mac, since the SSD can't be replaced on most models.
In Activity Monitor
Not shown. The Disk tab shows reads and writes since startup only.
In iKnowMyMac
The Mac health report includes SSD wear and data written, with battery health and cycles, in a one-page PDF.
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