Replacement external drive - should I get a new enclosure?

About 10 days ago when I ran Hard Disk Sentinel on my system it showed one of my external drives as only 19% healthy, with an expected remaining lifetime of 56 days.

As the drive, a 2TB WD Black 3.5", was bought in November 2013 and had a 5-year warranty I got the receipt and packaging, removed the drive from the enclosure, and took it to the supplying retailer, PC World. They called up the transaction on their system and said we'd need to contact WD. So while in the shop we logged in to my WD account that I'd created some years ago, noted the drive was registered, so input the faults. RMA accepted so posted it back to WD. A replacement drive has now been shipped.

As the enclosure is also nearly 5 years old, should I put the new drive in the old enclosure, or buy a new enclosure?

Any recommendations for a decent 3.5" enclosure, so many seem to be built very sloppily?

As the old one is USB 2 I'd also take the opportunity and buy a USB 3 enclosure.

Thoughts appreciated.

I have the USB 2.0 version of this CiT enclosure.Only issues: it comes without rubber feet and the power-on LED is at the back (and is unnecessarily bright). It is not USB-powered. I bought mine mainly because it supports IDE devices as well as SATA, but it's a solid enclosure. CiT do other models.

In the end I bought USB 3 version of the same brand as I've used for nearly 5 years, Dynamode.

The replacement drive arrived today and has been installed and is up and running ok.

Very pleased with the service from WD.