I've bought used as well as acquired used free drives from thrown out computers and have had good luck with them.
However my suggestion is that if your working with critical information have a sound backup plan or run RAID to avoid data loss or corruption no matter if new or used drives used.
Additionally check the drive with crystaldiskinfo to make sure it has a clean health record and isn't flagged in S.M.A.R.T as damaged bad sectors etc or malfunctioning with delayed read/write etc. If the drive shows a warning in yellow vs green good status then avoid using it!
https://crystalmark.info/download/index-e.htmlCloud storage is the safest for important data assuming your using strong unique password for this account, and this password isn't used with any other logon's elsewhere that the password can get stolen from etc.