You should look at the data sheets and technical specifications of the drives you want to compare. Each vendor gives detailed information about
- specified power-on hours (continuuous operation, divide by 24 or 8 for days/workdays)
- power on/off cycles (if your desktops are shut down frequently)
- head parking cycles (if you switch between idle and load frequently)
- warranty in years (on average, longer warranty indicates more confidence in the quality of the hardware)
- vibration & maximum number of drives in a system (usually up to 6-8 for NAS drives, no limit for enterprise drives)
- number of bytes read until an unrecoverable read error is encountered (on average, can be mitigated by using file systems like ZFS or btrfs)
- acoustics/loudness (should not be underestimated on desktops)
- power draw/heat (avoid very cold and very hot)
With those values you can then approximate if you should use the cheaper or more expensive ones. You should also into account costs for replacement of disks (procurement, shipping, installing/removing, disposing of old drives) and financial incentives (taxes, writing of over number of years, warranty on desktop systems).
If you just want the raw numbers, I suggest also taking a look at the Backblaze drive reliability statistics found on their blog.