“If it ain’t broke, don’t fix it” isn’t a maxim that holds particularly true in the world of computer software. “If it ain’t broke, spend nail-biting hours trying to make it work even better” is nearer the mark. Seductive promises of new features and trouble-free computing eventually persuade us to upgrade, leading to that same feeling of mild unease you get when someone tidies your desk: things we expect to find are no longer there, or have been replaced by things that are deemed to be a vast improvement.

This hasn’t deterred Mac users, though. Over 2 million copies of the new Mac operating system, Leopard, were sold in the first weekend, and it’s interesting to contrast the enthusiasm for it online with the comparative indifference towards the most recent Windows release, Vista, back in January. While Vista continues to be regarded as “not worth the hassle”, there does to be an almighty rush to adopt this particular Leopard.

I was one of those to make the knee-jerk purchase. As with most OS upgrades, many of the immediately apparent changes are cosmetic – indeed, the few Leopard-related gripes on various blogs seem to mostly concern the new transparent menubar. As “hiphopboy” commented on the Cyberclinic blog this week, “aside from nice email stationery and a couple of tweaks, it’s hardly life changing stuff, is it?”

Well, to call any software “life-changing” is immediately laying yourself open to accusations of ridicule, but Apple have built a backup facility into Leopard called Time Machine which, to exaggerate further, is a potential life-saver. Sheer laziness and stupidity prevent us from backing up files, but this feature makes it harder not to backup than to do so. You can pick up a 500Gb hard disk for £75, plug it in, and the work is done for you in the background. And at any time, you can go back an hour, a week, a month, see a snapshot of your computer at that moment, and either recall a single file, or, in moments of catastrophe, the entire disk.

Underneath, Time Machine is deeply sophisticated. For us, it’s just a couple of buttons. No tricky decisions to make, no trade-off between safety and drudgery. And as such, it’s going to be totally indispensable.

As is generally the case, my upgrade has required more than one attempt, and there are annoyances. Inexplicably, the word count facility in my word processor doesn’t work. And I don’t like the transparent menubar, either. But in the last week, Time Machine has already proved tremendously useful. Leopard might only seem like a sweetshop full of eye candy – but an idiot-proof backup system? That’s nearly worth £85 on its own.