This is mostly a question to answer with the disk survey, but I do wonder how many bad sectors mean that the disk is very likely to go bad soon. Obviously there needs to be a definition or finding of what “likely” means, what “soon” means and what “bad” means to have a useful answer but these are definitions that depend on the user. For a desktop user who cares about his data I’d say that the numbers are should be a 30% chance that the disk will either smart trip or have an unrecoverable sector in the next 3 months. For a server system with RAID I’d say that the threshold would be an 80% chance for the same problems in the next month.
I really should get going with the implementation of the disk survey to start getting the data for this.