Some tapes might be unlabelled
Obviously, you can’t run a successful tape archive if you can’t say for sure what resides on some of your tapes. Unlabelled media isn’t uncommon and can have a wide range of repercussions, among them legal risk – the data stored on a tape might be kept for longer than the mandated retention period, for example, or the organisation might be unable to respond in time to a regulator’s request.
The other issue is that if you’re attempting to restore a backup, poor labelling can add more than a few hours of downtime to the overall costs incurred by your business.
Damage might occur in storage
Stored correctly, magnetic tapes can last for decades – but the keyword really is ‘correctly’. All sorts of damage can occur to tapes in storage and transit, so it’s worth conducting regular reviews to check that your data is still recoverable. Dampness, extremes of temperature, fire and smoke damage are just a few of the things that can render tapes useless without expert intervention, and none of them are necessarily apparent until after the fact.
You might need to migrate to a new archive system
Some organisations run into trouble when they’re trying to restore data from tape archives because they no longer have the hardware or software required to do so. If you’re storing business records from two to three decades ago, it’s likely your IT infrastructure has gone through more than a few renewals in the interim.
Conducting a review of your tape archives should help you to determine whether or not the format of the data would be an issue or a bottleneck in a disaster recovery scenario, requiring a migration to a new system.
Some data might need to be destroyed
Finally, if you don’t have a formal data destruction policy in place, your tape archive may contain data that you’re required by law to delete or modify. This could include personal information on customers that you no longer have a reason to retain, as well as documents relating to former business partners.
Reference: http://blog.krollontrack.co.uk/pieces-of-interest/should-you-review-your-tape-archives/