I have always enjoyed watching squirrels trying to recall where they hid their nuts. Nature films like to tell us how good they are at recalling where each of their several stores has been cached, but my experience is that the squirrels of my acquaintance have much poorer memories.

They remind me of a friend, who was one of the best classic Mac developers on the planet. He kept his ‘off-site’ backups, including his very valuable source code, stashed in waterproof containers under his garden.

There are lots of potential problems in putting your backups under your garden, although interference by amnesic squirrels is quite low on that list. In those days, backups were on floppy disks, which did not take well to moisture, and if you were really unlucky could actually grow mold. Being electro-magnetic, each time an electric lawnmower passed over them, there was a real risk of data corruption.

I confess that I make off-site backups fitfully, but then store them over ten miles away, at my father’s house. I wish that I had the discipline to make a complete, snapshot copy every few weeks, and keep them there. But there’s always something better to do with the time, and I don’t have enough external 2 TB hard drives anyway.

So do you keep off-site backups?

You should. Time after time, when disaster strikes, it takes out all local backups. Whether it is a literal strike by lightning, flood, or fire, regular backups such as those made by Time Machine are taken out too. If you don’t keep copies of critical documents at the very least, in a location which is very unlikely to suffer the same fate, then you stand to lose the lot.

How much you move off site is, of course, a more difficult choice. Anyone required to complete VAT and/or Self-Assessment tax records is obliged to, at least for all their accounts records for the seven years or more prior to the current tax year. You will probably want a copy of your keychain and any other registrations and serial numbers, and all your significant work.

Such backups have changed considerably over the last few years too: with Macs generally shipping without optical drives now, burning a few DVDs-worth of key data to an optical disk is becoming increasingly unusual.

Cloud storage vendors are keen for you to keep your off-site backups in their cloud. Although a good selling point, cloud storage is not always as reliable as it seems. When natural disasters occur, they often affect a significant area. If you are trying to get up and running again and face difficulties getting capacious internet access, restoring a few hundred gigabytes of essential files from the cloud could be impossible for many hours or days afterwards, unless you are prepared to move some distance. In the region worst affected, there could be limited connectivity for two weeks or more.

Just as with local backups, you have to think through very carefully, and for a range of different disaster scenarios, how you might cope best. You should also be very mindful of the greatest hurdle: how often you make off-site backups. For there is no point in having the most robust system if the last time that you could find time to back up to it was many weeks ago.

Ask yourself how you would cope, and what you would do, if disaster did strike now. Would you end up digging up your garden in search of a handful of moldy DVDs from early in the New Year? Take a lesson from the more forgetful squirrels of this world, and bury your nuts where you can find them. Often.