Notes from the workshop / 9 September 2026
Why storage is chosen by endurance, not capacity
Capacity is the number that sells a drive. Endurance is the number that decides whether it's still healthy in year four. What TBW means, and why we check it before a drive goes in a build.
A drive listing usually says one thing: how many terabytes. That number says nothing about how much writing the drive can take before it starts to fail — and every SSD has a finite amount of writing in it.
What we write instead
Capacity and endurance class together, on the line item: "1 TB NVMe, high-endurance class, 600 TBW rating or better." TBW — terabytes written — is the manufacturer's own rated limit for how much data a drive can take over its life. A busier build (video, a large game library) gets a drive rated further up that scale: 1200 TBW class rather than 600.
Why it matters over four years
A cheap drive at the same capacity can carry a fraction of the write endurance of a good one, for a small difference in price. The failure isn't usually dramatic — a drive that starts throwing errors, or simply stops accepting writes, once it's used up its rating.
- One drive doing that is an afternoon lost and a restore from backup.
- A fleet of identical low-endurance drives, bought together, tends to wear out together — in year three, all at once, as a replacement project nobody budgeted for.
- The price gap between a low- and a high-endurance drive at the same capacity is smaller than an afternoon of downtime is worth.
If a specification lists only a capacity, ask what the endurance rating is. Often nobody's checked.