The speed of a wireless drive will depend on the strength of your Bluetooth or even the strength of your wireless connection in general. Some HDD products will favour speed over storage, whilst some also wireless too. A USB 2.0 HDD will be able to transfer data much faster when compared to a USB 1.0 drive. This will depend on the RAM of your computer and the USB section of the drive. Some hard disk drives are faster than others. The size of the HDD may also depend on how much data it can store, with some devices offering a whopping 5TB of space! Speed External HDDs are usually connected to a computer via a USB cable.
If you do run out of data then it is more than possible for you to delete data before you go on to store more. The storage of the HDD will ultimately determine how much data you can store at any one time. The external HDD you choose will largely depend on the reason for your purchase, the amount of data that you need to store and even the speed at which you need to store that data. Some of these include the USB 3.0, the USB 2.0, wireless devices and even the Thunderbolt as well. External hard disc drives (HDDs) come in many different variations.