It is ONE tool to use.
There is also the manufacturers diagnostics.
As well as other tools. HDDSentinal, HDDTune, etc, etc.
But...a drive that shows 100% health today can still die tomorrow.
Seriously. I've personally had that happen.
The only true way to protect your data is a good backup routine.
If the drive dies, you replace it.
If it is still under warranty, free replacement.
Otherwise, $$ replacement.
Your data should never be at risk, or trusted to some software that says "100% Health".
Most programs should be reading the same smart data, meaning they should report the same values.
For a HDD, mount it properly and make sure it isn't jostled around or dropped. That will maximize lifespan.
Always, always, always have a backup.
Done right, nothing is too large.Backup is a bit complicated when I have 10TB+ of contents
Which backup you use usually? Cloud or external HDD?