Ezra has a question for the table:

"As I mix, I often find myself trying not to use songs that I've used on previous mixes. Now, of course one tries not to send one song to the same person repeatedly, but do you or others worry about repeats in the basic mix-construction process?"

I dunno, part of the fun of making a mix is coming up with a mix that is substantially new. So I would say that a repeat is perfectly fine, so long as it is used in a different way. On the other hand, I think its acceptable to make several slight twists on the same mix to send to different people at the same time, cause there it isn't making several different mixes, just a personalized version of the same one. The mix I'm making now I don't want to have many repeats from earlier mixes i've made, because the goal of this mix is twofold: a) to show friends what sort of music they're missing by not being around me constantly, and b) to prove to myself that i've found a new world of music over the past year or so, and have enough songs from this incarnation of my life to make a cd. Both of these ideas lead to picking music that couldn't have been on earlier mixes. Now this isn't entirely true, since several songs that i've listened to previously i've listened to a lot recently, e.g. Losing My Religion and Under Pressure.