Wd performance bad

my wd sata drive model number is : WDC WDS120G2G0A-00JH30 and its health is only 81% can you tell me what’s the reason ?? and how to improve performance for that / i need to replace this drive ?

There might be chances that your hard drive consists of bad sectors. When a good hard disk comes up with one or more bad sectors, the disk goes bad; and, when such a situation occurs, the data stored in the bad sectors may get lost. There are scenarios when the cause of bad sectors could be a faulty drive head. In such cases, there is a likelihood of spreading the issue to several other sectors of the disk. Hence, in situations where the hard drive experiences one or more bad sectors, it is highly advisable to back up the disk data or fix the bad sectors instantly.

Further, I suggest you to check the below link that explains all the measures to check the health of any hard disk:

https://www.stellarinfo.com/blog/how-to-check-hard-disk-health/

Hope it will help!!