docs(NAS): Extend disk replacement docs

docs/src/hardware/nas.md

@@ -40,9 +40,11 @@ In my tests with no, but just test workload, the average power usage of this NAS
 When a disk fails, it should be replaced. To replace a disk it's important to locate the correct one. It's advised to write down the disk's serial number and it's physical slot of the NAS. Since the TerraMaster NAS has no indicator LED, it's only possible to locate the drive in TrueNAS using `ls -l /dev/disk/by-path` otherwise.
 
 <div class="warning">
-It's better to replace a failed disk offline. Shut down the NAS, switch the disk, turn it back on. In worst case, e.g. when replacing the wrong disk, the pool will not be found and considered offline. This prevents disaster.
+It's better to replace a failed disk offline. Shut down the NAS, switch the disk, turn it back on. In worst case, for example when replacing the wrong disk, the pool will not be found and considered offline. This prevents disaster.
 </div>
 
+Before adding the disk to the pool, run a SMART test of the type `conveyance` to check for issues from shipping.
+
 A short tutorial about the steps in TrueNAS can be found here:
 
 <iframe width="100%" height="480" src="https://www.youtube-nocookie.com/embed/7ZKDPcSRsKY" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>