Advantages of External HD vs Enclosure?

Though it's been a while, last I checked a USB enclosure + HD were cheaper than an external HD of the same size.

Any advantage of one over the other?

Also, chances are, failure within a year is more likely attributed to the fact that they were still carrying around IDE drives in an external enclosure that are designed to be sat in a still PC case for only as long as the warranty lasts. There is extra wear and tear on drives that are moved around a lot.

A certain amount of abuse is sort of expected on an external hard drive. This is taken into account when the drive is designed, so it doesn't need to go back before the warranty is up.

Now I did say they didn't take theirs around as often as I did, but I usually take my drive around with me religiously. In comparison, they only take their drives around with them about once a week. That is still considerable wear and tear on a drive that is designed to sit in a still computer case for 12 months.

That would probably have the most bearing on their failure.