There is a difference between an external hard drive and an enclosure.
External hard drive is a self-contained unit-a case with the hard drive inside.
An enclosure is for an existing hard drive, such as the one in your computer. The enclosure allows you to put the computer hard drive into it so you can use it for an external drive.
Examples: 1) I had an HP laptop. It died due to reasons NOT related to the hard drive or motherboard. Since the drive was still good, I purchased an enclosure, took the drive out of the HP, put it in the enclosure and now use it for back-up purposes.
Several years ago, I bought an external hard drive. As (bad) luck would have it, at about the same time the HP laptop died, so did the external hard drive. Good luck that the drive in the now-defunct external hard drive also fit in the enclosure I bought for the HP drive. So now I have 2 drives I can still use in the enclosure.
Bottom line, if you purchase an external hard drive you will NOT need to also buy an enclosure.
Which also means that if the drive from your previous laptop is still good, you can use it in an enclosure without having to buy an external drive. Of course this will only work if you know for a fact the drive is good.
The only thing to be aware of with an enclosure is making sure the drive will fit into it. Older, bigger hard drives will need one compatible with the size of the drive. And smaller, newer drives will need an enclosure they fit into.
I still have the older bigger hard drive from my first custom built Win XP desktop which I put into an enclosure. One day I will pull it out to see if it still works.
Putting the drive into the enclosure is an easy process. If I can do it, anyone can.
edit to add: if you purchase a bare bones replacement drive and an enclosure for it, the cost for both would likely be more than a self-contained hard drive.
Enclosures for an existing hard drive can be cheaper than an external hard drive unit.
And my opinion on backups: always back up to at least 2 external sources.
Suppose you use DVDs and have to use them in the future. You get through a few of them, get to the next one and the disk is so scratched it can't be used. You get stopped in your tracks and cannot complete the process.
Or if using an external drive backup, you discover that drive has died or for some reason the external drive mechanics has failed. (the hard drive may still be good) If you want to use your backup, you won't be able to unless you have another source.
Edited by Queen-Evie, 18 June 2016 - 10:30 AM.