Computer Learning

[sharpshorts]

Either way ... I leave mine hooked up for days at a time, sometimes I hook it up to my other machine(s).

When it's plugged in, you can save stuff to it instead of to your C:\ drive.
This is particularly useful if you are worried that your main machine's "Used" space is getting low...

Although this is changing quite rapidly, the GB size of external hard drive's memory is very cheap
compared to internal drives, especially Solid State Drives.
A 1000 GB external drive sells for less than $90 vs. an internal 128 GB SSD selling for around $120...
...think of external drives as a bigger (albeit slower) version of portable ZIP or "Flash" drives...
You can easily carry around the external drive and access the stuff on it from virtually any other computer.