Hard Disk Monitoring

hi
how is my hdd remaining lifetime is more than 100days if health is 100% and no reallocation sector or no pending or uncorrectable sector are all 100 with no problem? how do a user can estimate remaining time to avoid getting any problems ? i've used my harddisks in USB dock-Unitek Dual HDD dock- connected to laptop. so maybe less than 20-30times i've moved them around,nostly stationed on floor with free air around it. I used mostly in read mode -downloading and using it as archives of everything - but anyway I've written alot on one with -30tb after 5years- and 17TB on another one after more than a year. i want to assure any buyer that these works for XX months or years if you still used it as archive mode. i've attached everything from S.M.A.R.T to SURFACE REPAIR TEST to overall page .

Thanks in advance

Please check the Help which describes how the Estimated remaining lifetime calculated:

https://www.hdsentinel.com/help/en/54_pot.html

This page describes that even if no problems found and the Health is 100%, the Estimated remaining lifetime can decrease during the life of the hard disk drive - and then stops at "more than 100 days".
This is an indication that the device reached the end of the designed lifetime. It CAN still work for long time (even for years, especially if used with best care: with proper cooling, proper power supply, no shock/vibration etc) - but we can't say this for sure.

Maybe you can see that it is not a strict countdown: as long as the Health % remains, this number also remains at this level, so it does not mean that the hard disk will surely fail.

This value designed to suggest when (in a mission-critical environment) we should consider/plan replacement - as near/after the designed lifetime, sudden, unforeseen failure is more likely.