If your computer has a DVD drive, then picking up a cheap stack of rewriteable DVDs can feel like a sound way of archiving your files. But is it safe enough to rely on?

Pros of backing up to DVD

Bought in bulk, blank optical discs (CDs, DVDs and Blu-rays) can be one of the most cost-effective ways of storing your data. A spindle of 100 blank single-write DVDs bought online, for example, gives you a total of 470GB for around £18.

Space per disc is limited, however. A blank DVD only holds 4.7GB of data unless you opt for more-expensive dual-layer discs. Blu-ray is roomier, with 25GB (or 50GB for dual-layer discs), but few PCs have built-in recordable Blu-ray drives, so you’ll need to factor in the cost of buying one (around £80).

Cons of backing up to DVD

There’s a confusing array of disc formats, and it’s easy to buy ones that aren’t compatible with your hardware. 

The most common types will only let you write to them once. Look for rewritable discs (labelled ‘RW’) for backing up, though they are more expensive (around 12p per GB).

All optical discs have a limited life span; reliable brands claim to last for up to 100 years, though the reality is that many cheap discs may not last a fraction of that.

Discs need to be kept under very specific conditions. You should not write on them with a pen or use sticky labels, as ink and adhesive can corrode the disc. They should be kept in protective cases in low humidity, at low temperatures and out of direct sunlight. Even still, it is easy for valuable files to become victims of dust, scratches and other damage.

Verdict:

They’re undeniably cheap, but DVDs are a clumsy, awkward backup solution, and the delicate nature of the discs themselves makes them highly unreliable. If you have a lot of old files archived to CD or DVD, we recommend transferring them to an online storage service or hard drive soon.