Assuming Windows, Robocopy has a multithread option that might be able to do multiple copies simultaneously. Haven't used it. Not sure. Free. Worth looking into.
Some old, old drives had a problem where the spindle wouldn't spin, a phenomenon known as "stiction." Drives made in the last -- maybe -- 15 years seem to be immune.
One other remotely possible issue would be "bit rot." That's where the magnetic polarity of a single bit could change over time, often being influenced by neighboring bits.