1TB hard drive, currently available for about £75 in the UK or $85 in the US
I'm not sure how many virtual column inches here at Pixiq have been devoted to our exhortations that you should implement a proper backup policy for your images, music, and other precious electronic files, but it is not insignificant. There are guides to establishing a workable routine, reviews of different pieces of hardware and software, advice for keeping your data safe when travelling, and now I'm going to throw personal experience into the mix.
Before anyone starts to gaffaw, no, I haven't just lost thousands of images in one catastrophic swoop. This is something that happened to someone else, but has had an impact on me. And still please don't gaffaw.
Over the past few months I've been working on a project that's a collaboration between me and a heap of other photographers. I've been in charge of curating it, which has been an exercise in military-grade planning. If I were to tell you about the number of spreadsheets I have, covering the most miniscule of details, and the different documents that I've going out and coming in, you'd die of boredom, but it has all been a necessary part of the process.
For the most part, my excessive attention to organisational minutiae has proved successful. But still, somewhere, despite colour-coded spreadsheets and meticulous filing, I slipped up. One of my collaborators wriggled through one of my barrage of checks and hadn't sent me a high-res JPEG of one of his images.
I sent him a quick email asking him to deposit the image in question in the Dropbox we'd been using for the project. When I read his response to my request, my heart sank like a stone. He couldn't send me the high-res version because he'd suffered a hard drive failure and he'd lost his images. They weren't backed up. Poof! All gone.
For the project, this is a bit of a disappointment, but it is in no way catastrophic. For the photographer, on the other hand, this is a huge collection of images that he's lost because he didn't have copies floating in the cloud or secreted away on another hard drive or two, or preferably both. I don't even want to think about how devastated he must feel.
If he'd have sent me the JPEG when I'd originally requested it, or if I'd noticed that I didn't have it initially, at least I would have had a copy. But it wouldn't have saved the rest of his images on his hard drive.
There are a bundle of different means of keeping your data safe. They don't necessarily cost the earth, either. Please don't be one of these people who loses important data because you don't have a backup plan in place.