We recommend that you replace older disk drives even if they have not failed. As disks age, the chance that they will fail increases. It is always better to replace a disk before it fails than to wait for it to fail and have to restore data from a backup or replace a disk on a Mac which is currently in use.
Most SSDs (Solid State Disks) contain wear indicators which show how much longer they can be used. These count down from 100% of media life remaining down to 0%. An SSD should be replaced once its media life remaining is less than 10%. The media life remaining for a particular SSD is shown in the disk tile in the SoftRAID application. The SoftRAID Monitor will also warn you once an SSD has less than 10% media life remaining.
We recommend that rotating disks (HDDs) in laptops be replaced after 5,000 hours of use. These disks are smaller and less reliable than the disks found in desktop computers and servers. This amount of use corresponds to 2–3 years of use by an average user.
We recommend that SSDs in laptops be replaced after 20,000 hours of use. SSDs last much longer than HDDs in laptops.
We recommend that disks in desktop computers be replaced after 10,000 hours. While these disks are more reliable than the smaller ones in laptops, they are subjected to the repeated stress of being turned on and off. 10,000 hours corresponds to 4–5 years of use in an average office environment.
We recommend that disks in servers be replaced after 20,000–25,000 hours. These disks are usually properly cooled and are not subject to the stress of being turned on and off, but they often experience periods of intense activity. This number of hours corresponds to 2–3 years of use in a server which is on 24 hours a day.