^^^That's a great point. Having the ears -- along with the awareness, and the analytical mindset (applied as both foresight and recognition) -- to know what you're looking for and when you've found it is one of the most important skills of being an audio engineer.

Being able to "hear" in your mind's ear what you're striving for before you turn a single knob...and then knowing which knob (if any) to turn to achieve that ideal. That's arguably the most valuable talent.

It's not enough to be able to listen to something on playback and think "this isn't doing it for me." If you can't identify what is needed for it to "do it" you haven't done your 10,000 hours.

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Semi-somewhat germane to this topic, a little anecdote just 'cuz it's fresh in my mind: I've been working with a producer on a number of projects over the last two years, and this guy is really dialed in to phase discrepancies between the DI and mic on a bass guitar.

And by "really dialed in" I don't necessarily mean he's bringing any enhanced sensetivity or ultra-refined ears or even any value... he just hears these phase differences and wants to do something about them. So we spend a lot of time listening to playback while nudging tracks relative to one another, and some relationships he loves and others bother him and demand a fix.

I'll be honest: While I can hear the differences, I can't for the life of me understand why any of them would bother someone, or why the "fix" is in any way a sonic improvement over what we started with. But he's paying the bills, so...

Point being, he's got this ideal sound in his head, and he knows that tweaking the relationship between mic and DI will achieve that ideal. If he had neither the ideal nor the knowledge of this (one) way to achieve that ideal, he might waste a lot of time casting about blindly trying to throw anything against the wall to improve the sound...or, he might save a lot of time and move on to other more important things.

:shrugs: