I started running Runtime Repair a few days ago and noticed Remove Unused Dials was turned on, so I aborted the process.  I then realized I did not know precisely what this does or why it is on by default...  What constitutes an unused dial?  Surely it isn't just dials with a value of zero, as that would cause expressions and all kinds of things to be deleted.

So did I screw up or is this nothing to worry about?

When would one want/not want to run the program with this option selected?