Wise old monkey's habits. 
I have had clients return 15 years later and ask for a new master. 
I still have my Atari floppy disks with my midi files.. that's how far back my back ups go! 
I have a shoe box with every C drive that was ever in my DAW from 2000 onward.  
Box of 1/4 " reels and DAT tapes I can't play but .. I'm just glad I never could afford 2" tape :)