PDS does not recommend using the same set of disks each time that you create a backup. Both the data on the hard drive and the data on the backup disk can contain data discrepancies or corrupted data. To reduce or eliminate the chance of these problems, use different sets of disks every time you back up your data.
For example, if you back up the data each Friday, using at least four backup sets provides better protection. Label these disks Friday 1, Friday 2, Friday 3, and Friday 4.
If you reuse tape backup media, be sure to replace these regularly to guarantee performance.