external USB drives could be a PITA. I don't buy pre-build drives, but most enclosures I bought were a PITA, suffering from input/output errors. I had a lot of discussions with vendors and always got my money back.
As a rule of thumb, if the USB controller (again, the USB controller, not the HDD) turns off itself and or the HDD after an idle time, then input/output errors are a safe bet. In my experiences this usually happens after an idle time from around 10 minutes.
I'm using fantec DB-ALU3e enclosures. The USB controller is always on, it never turns off anything, no input/output errors, unless the HDD is broken.
Note, don't get another enclosure, such as the DB-ALU3-6G from the same vendor. They suffer from input/output errors, because the control tries to be smart.
The fantec DB-ALU3e enclosures has got USB3 and eSATA connectors, but can only be equipped with a maximal size of 4 TiB. I'm only using USB. Works on USB2 as well as USB3 ports without issues.
The first time you might not be able to blindly build in a HDD into such an enclosure, but it's that easy, that every unskilled person can help you and with some practise you likely could DIY.
FWIW I own one old pre-build green USB WD drive. It does park the HDD's heads after an idle time, but if it gets waked up, it does not suffer from input/output errors. It's much likely the HDD that handles this and not the USB controller, however, to avoid that this drives goes to sleep and is woken up immediately, I removed software such as GVFS (dummy package), have software such as smartd not enabled, since all this software does wake up sleeping drives, right after they switched into stand by mode, which would cause my WD drive to park and release the heads every 30 minutes.