No way to tell how much life is left ... could work just fine for another 10 years.
Pending sector count ... in very basic simplified way ... data is written on discs inside the hard drive in sectors, each sector being 512 bytes or 4 KB ... as the drive writes or reads the data from such sectors, it monitors the quality of the signal read or written so it can figure out when the material in that area becomes weakened and the drive can no longer be 100% certain that what writes in that area will remain readable after some time.
Think of it like having a 0..100% scale for each sector and that the hard drive can read the data with as little as 50% and your sector now has a number that's maybe 70-80% when every other sector is above 90%
So the hard drive can read the data from that sector and maybe sectors to the sides of this sector and write it down somewhere else and mark that area as "don't write here anymore" and nothing is lost and drive keeps working just fine.
Depending on how that weak spot has developed (appeared) it could be that over time the area enlarges or other weak areas pop up or it could be nothing, with the drive going on for years just fine.
