I have a CD player on board, but I never remember to bring CDs along for sailing. Once in a while on a maintenance day I bring one or two. I still haven't figured out MP3s, and the image of blue teeth is thoroughly offputting.
During the SHTP I thought many times that it would be a good idea to keep a log of the songs running through my head, which would change every hour or so. (I find the term "ear worm" just as unpleasant as blue teeth.) But I didn't.
Of course, once in a while I sing aloud. Another benefit of singlehanding.