I mean, if you are directing actors to do one thing and then directing them to do something else entirely because the one thing you wanted them to do may not work, then you are just shattering their confidence in the project.
Age appears to be best in four things; old wood best to burn, old wine to drink, old friends to trust, and old authors to read.
Just because you know umpteen billion scales, it doesn't mean you have to use them all in a solo.