External USB hard disk - constant access

I have an external USB hard disk that I use for backup. I'm using Carbon Copy Cloner to clone the iMac's fusion drive to this external drive. This is scheduled to occur each night at 9:30pm. I do not use this drive for anything else. I have included this drive in the list of locations that Spotlight should not search.

Access seems constant, based on sound. I am concerned that the drive will fail prematurely because of this.

Appreciate any guidance.

iMac (Retina 5K, 27-inch, Late2014)

macOS Mojave (10.14.6)

Macintosh HD = 1.12 TB Fusion Drive (original)

External USB drive = WD 2TV 2.5" conventional HD