Five things to look out for

1 Hard disk drives have moving parts and are vulnerable to drops. Solid-state drives are much more resilient.

2 Some drives are pre-configured for either macOS or Windows. This can usually be changed.

3 Transferring a large batch of image files will usually take longer than shifting a single video file of the same size.

4 All these drives are powered by USB or Thunderbolt, so don’t require a separate power brick.

5 Many manufacturers bundle extras like backup software, data encryption or even cloud storage.