Sheesh jford, sounds like work!

At work we do a weekly backup, daily incremental, then make a copy of the backups (in another location) as they complete. This copy then gets replicated/sync'd to another location.

The backup system is located in a co-hosted location (with backup power, auto generators, multiple tiered INET connections; fiber, cable, satellite you name it, etc). Backups are then verified, with any fails generating an alert to us.

Then these backups get copied to location 2, which uses a mirrored RAID that is replicated/sync'd with another mirrored RAID drive (over VPN) in location 3 .. you can watch the stuff replicate from place to place. It's actually pretty cool.
If even one of these RAIDS fail they can rebuild on the fly, and we still have 2 other copies available.
Keeping a month's worth means keeping three 6TB RAID arrays running .. but we ain't losing no data.

80% of businesses that lose their core data (whether due to failure or intrusion) go out of business within 3 months.

Make your sound your own!
.. I do not work here, but the benefits are still awesome