Choosing drives that survive heat and power cuts. Warranty length tells you less than workload rating and how the drive behaves when the lights go out.

A drive that fails quietly in a warm room is a more common way to lose data than any dramatic failure.

Read the workload rating

The figure that matters for a NAS is terabytes written per year, not the headline capacity or the warranty period.

Sudden power loss

Cheap drives cache aggressively and lose the cache when power drops mid-write. This is where an unremarkable outage turns into a corrupt filesystem.