Alternatively, you may choose just to back up the most important files and documents from your user libraries, such as text documents, photos, films, music and stored email.
While there’s a big difference between the technology used in traditional hard drives and SSDs, both have a limited lifespan, and this is why warranties are relatively short - typically two or three years.
What’s important is that you have a well-thought-out backup process and you don’t rely on any single drive to store precious files.
Compare this with the older drives using USB 2.0, which would limit speeds to around 35MB/s, or only one-third the speed.
So in real terms, your 100GB of media files would take close to an hour to transfer with USB 2.0, or under 20 minutes using USB 3.0.
We give a value rating based on how much each gigabyte of storage is costing you for each drive.
Particularly with a 3TB drive, you can expect to find storage for under 4p per gigabyte now.
This means that it should withstand being dropped 26 times onto a hard floor, once on to each face, edge and corner, from a height of 1.22m.
Flash storage - more commonly known as SSDs - can survive more brutal treatment, and some portable drives are even water resistant.
Most portable USB drives are powered by the connected computer, so you can use them on the move without the need to plug into the mains or use batteries.
Some will even connect your phone or tablet and let you extend storage that way, or allow you to transfer or open files.
HDDs are a type of non-volatile storage, retaining stored data even when powered off.