I can understand the concepts of a break-in period. Makes sense actually, particularly with tubes, which I have. Then again, I have had s many variables with my system that it is hard to isolate the sound changes due to one factor - like a break-in period. Examples include re-ripping CDs to better formats, populating my Roon Nucleus SSD, playing so much new music. AND NOW, I just investing in a new set of Tube components and speakers (moving the existing to another room). Way too many variable in my life to isolate anything down to a break-in period, but conceptually, I understand. I agree with earlier comments though, I am trying to sit back, chill, and "listen to the music play."