When I first began teaching 23 years ago (yikes!) I didn't keep track of song repertoire the way I do now. I also often felt pressed to sing lots of songs (still do) but would only sing them once or twice and then be done with that song. Now I keep a list of repertoire learned and frequently revisit songs. I also try to "double dip" concepts and skills and repeat songs learned in previous grades but with a focus on a different concept. That So Mi song that has Do, Re, Mi at the ending may be...