I thought I would share my answer here.
Floppy disks have a RELIABLE life expectancy of a year or two. My experience has been that they usually last longer, but you can’t depend on that. If you store dozens of floppy disks, at least some of them will lose data within 2 or 3 years.
Of course, there’s the not-so-small matter of having access to a device that can read your media. For instance, when that old 3 and ½ inch floppy drive dies, how easy will it be to find a new one? Even if your storage media works after prolonged storage, you need to consider availability of a device to read your data!
That being said, let’s talk about backup best practices. The only reliable way to store digital data is to do two things simultaneously:
- Make MULTIPLE copies to different kinds of media and then store those copies in different locations
- Copy all your backups to new media frequently, such as every few weeks
For instance, I make most of my backups to hard disks that are kept spinning and in use in different computers. Some of those hard disks are here in my home, and others are in remote data centers in other parts of the country.
Most of my backups are less than 2 hours old. Some are 24 hours old. It’s all done by software, whether I am at the computer or not. Many of the backups are made while I am sleeping. (I leave my primary computer powered on and running 24 hours a day.)
In addition, I do keep some additional backups on CD and DVD disks, but I don’t depend on those alone. I consider these to be secondary backups; I only use CD and DVD disks to store secondary copies of information that is already backed up elsewhere. The CD and DVD disks are always thrown away after 30 days and are replaced with new backups.
In my (admittedly biased) opinion, any backup that is more than 30 days old is potentially worthless.
Next, I also TEST my backups. I don't trust anything that is stored on a computer. Once a month, I restore a file or two from some of my backups -- just to make sure that the backups are still being made regularly and are capable of being restored. I always do this on the first day of the month because that is an easy date to remember.
Many times I have heard or read the comment, "Well, I thought it was making regular backups!" That statement is usually made in the middle of some disastrous situation.
Have you tested your backups?