"Storage is almost free so you can easily afford to wait just about forever." Forever is a long time. The point made above is valid, which is that data devalue

"Storage is almost free so you can easily afford to wait just about forever." Forever is a long time. The point made above is valid, which is that data devalues greatly over time. Take in point the famous case of the Zodiac Killer: https://en.m.wikipedia.org/wiki/Zodiac_Killer https://en.m.wikipedia.org/wiki/Zodiac_Killer. Recent work seems to suggest that his encrypted messages are close to being solved (decrypted). If in fact we do have a solution and we've learned his identity then this information is of much less value now than if it would have been available 50+ years ago. For starters, it seems the killer is now dead. Thus, being able to decrypt his messages after this lengh of time is of little practical use other than of academic interest and or offering some resolution to his victims' families. The value of encrypted data held by the NSA and GCHQ in anticipation of finding a decryption key will rot in exactly the same way. In short, it's only worth keeping the data whilst it's potentially useful.