All drives die. Sometimes right away sometimes it takes ages. If you have backups it doesn't matter if the drives are new or used because your data is safe. If you don't it also doesn't matter because they'll all fail at some point and there is no way to know whether any given new drive will fail before or after a given used drive.

For me I can get 2-3 good condition used drives with warranty for the same price as a new drive so it doesn't make sense to buy new.

When you price it out for a large server buying used will give you a full backup + your parity disks for the same price as a single server built with new drives.