So I learned this lesson today. Working on a song - being very conscientious about gain staging in the recording process and have been mixing as I go -- getting to a stage where the mix has revealed itself and I'm pretty clear on where I'm going.... then slowly and subtly over time realizing the mix got away from me -- particularly with the levels. Basically mix creep or gain creep... a little boost here, a little there, -slight re-balance, boost, boost, re-balance, boost -- yikes why am I redlining? The good news was because I was really conscientious about gain staging during recording it was an easy fix (once I abandoned the fear of losing my mix) - plus I used master track folders which allowed me more control over groups of instruments --- but holy cow I was surprised how out of whack things got with those faders being pushed up and up. Good lesson.