An aside.. I bought a used Adcom DA700 back in late 90's? anyway it cost me $250. I used it and even returned a highly praised $2300 greatest thing since .. DAC because it was no better than my Adcom,, back in 2010.
Finally in 2018 after upgrading speakers my dealer loaned me a $7000 SACD.DAC.. and gee it did sound a little better.
So for a 1% improvement, it cost me $7000 vs the $250 investment I had prior. Was it worth it? yeah, Audiophile style.
I still have about 2,500 CDs..
And plenty of them, including old ones sound great.