Hard drives are the most commonly replaced hardware item but, until recently, actual failure rates have been a matter of anecdotal experience and small scale research. Now there are hard facts.

Recently released data derived from Google's server farms proves hard drive failure rates take a big jump after two years and then keep on increasing. They typically don't last the five years the vendors say they should.

If you don't back up you're definitely asking for trouble. What are the options for Mac?

Retrospect has been the traditional choice. Retrospect is powerful, you can set schedules and do incremental backups that allow you to move back in time to find documents that may have been erased or corrupted. It backs up to hard disks, CDs and tapes for off-site storage.

But it's not without a downside. Retrospect can be complex to set up and retrieving data from it's encoded archives can be time consuming. It's incremental backup files continually grow in size. Retrospect's development has lapsed lately. It is no longer owned by Dantz but has been sold to EMC Insignia, so we'll see if they continue development of this product.

Another choice is DejaVu, an inexpensive and elegant program that can be scheduled to match your backup to your original files nightly and additionaly archive changed and/or deleted files so you can go back and retrieve a document as it existed, say, three days or three weeks ago. DejaVu is effortless compared with Retrospect and is continually being improved by it's developer. As you can probably tell, it's our choice.

There are a number of other options reviewed here, your best choice depends on your exact needs. Don't forget to take a full backup off-site at regular intervals for disaster recovery. You might want to consider paying a monthly fee to backup to an off-site server.