My experience with my drives is that Windows is faster to complain about bad sectors and the SMART is not as reliable as you may think
Well, unfortunately, I have to test up to 10 drives a day in 8 different testing servers, all day, everyday; and I can tell you that S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) is very accurate and a godsend. It is very wise to get the data off when a smart failure happens and replace the drive. Temperature, Rotational speed, read errors, and other data that SMART utilizes is cold hard data and statistics and if you continue to use a drive that SMART deems on it's way out (as many of my clients do) you can buy a week, a month, and yes maybe a year, but you are prolonging the inevitable and most likely suffering with performance issues during the wait for the drive to totally die.
Get the data off, buy a new HD, and give the magnets to the kids or grand kids to play with from the old drive... they are so cool. The point is, bad sectors usually lead to more (remember the old MFM, RLL days when we low level format... that was different technology, any SATA or PATA drive that needs low level formatting is ready for the trash, it should NEVER be done, it is on the way out, error mapping for the new technology drives is done at the factory... once)