Huh. So many fixes in there are listed as 'replace head(s)'. I didn't realize that was a common fix for hard drives, thinking it would require near cleanroom conditions to ensure no dust got into the drive as its being worked on, and that it would be much cheaper/faster to maintain backups and swap in a new drive.

It's a "fix" in the context of data recovery business. The aim is to get the drive in a working condition for a few hours, just enough to get an image of it. After that the drive is trashed (or more precisely, put in a big box so it can be used as a donor for other drivers in future)

I've read that the replacement heads also often get damaged while reading the media during the recovery process.