Buying guides
Short, plain-English answers to the questions that actually decide a hard-drive purchase — written by the same people who built WorthaByte’s scoring.
- CMR vs SMR hard drives: which is safe for a NAS?
The single most important spec for any RAID array — why SMR can stall a rebuild, and how to tell which one you're buying.
- Are recertified and refurbished hard drives safe to buy?
What “recertified,” “renewed,” and “refurbished” actually mean, when the savings are worth it, and how to lower the risk.
- What's a good price per TB for a hard drive?
Why price-per-terabyte is the only fair way to compare drives, and how to tell a real deal from a fake sale.
- RAID levels explained: 0, 1, 5, 6, and 10
What each RAID level costs you in capacity, how many drives can fail, and which one fits a home NAS — with a calculator to size your array.
- The 3-2-1 backup rule (and why RAID isn't a backup)
Three copies, two media, one off-site — what the rule means, why a RAID array doesn't count as a backup, and how to size the drives.
- Helium vs air-filled hard drives: does it matter?
Why high-capacity drives are sealed with helium, what it changes for heat, power, and reliability, and whether it should affect your buying decision.
Guides are general buying advice. For the exact factors behind any drive’s rating, see the scoring methodology.