I used to travel around the world upgrading software and hardware in computer rooms. In one place people smoked in the computer room - because their boss did, so they ignored the ban too. In that one computer room the hard disks had to be reformatted approximately once every two or three months, due to errors (and that would update the internal sector error list so that the disk could continue to function). This never happened anywhere else, the equipment was exactly the same everywhere but disks didn't fail at the other sites. Can't be sure but the only difference with that site was that people smoked in the computer room (those disks weren't airtight).