I have boxes and boxes of "back up" and "seconds" CDs and I need to do some consolidating. I have a few questionable CDs: Carpenters "Yesterday Once More" (1998) and "Gold" (2004) - which one should I keep? Even though one is remastered by Richard Carpenter and the other by Bernie Grundman, they sound almost identical. I didn't know if there were any mixes specific to either CD? I know that this is probably a stupid question around here, but do I really need to hang on to my Stones mid' 80's German London CDs?