Estimate SSD lifespan from TBW rating, drive capacity and daily write volume.
SSD manufacturers rate endurance in Total Bytes Written (TBW) — the total data volume the drive is warrantied to absorb before flash cell wear meaningfully increases failure risk. Subtracting cumulative writes so far from the rated TBW gives the remaining write budget, and dividing that by the current daily write rate projects how many more days of use remain at that rate. This is a linear projection assuming a steady write rate; workloads with growing write volume (more logging, larger databases, heavier caching) will exhaust the remaining budget faster than this estimate suggests.
Remaining lifespan in days
remaining_days = (rated_TBW − total_written) / daily_writes
Run `smartctl -a /dev/sdX` (or /dev/nvme0n1 for NVMe drives) and look for 'Total_LBAs_Written' (SATA SSDs, multiply by the logical block size, usually 512 bytes) or the 'Data Units Written' field (NVMe, each unit is 512,000 bytes) to get cumulative host writes.
Not necessarily — TBW is a conservative warranty threshold, and many SSDs continue operating well beyond their rated endurance, though the risk of uncorrectable errors and eventual failure increases as flash cells wear out, so treat exceeding TBW as an increasing risk rather than a hard failure point.
Write amplification means the SSD controller often writes more data internally than the host requested, due to wear-leveling, garbage collection and how flash pages must be erased in larger blocks before rewriting — actual NAND writes measured by the drive's own SMART data can exceed host-level writes by a meaningful factor depending on workload pattern and drive overprovisioning.