Mixing and matching - what do you do?

I'm still learning how to teach my classes. So far I've learned two Rounds 42 and 44. I was curious - for those of you more seasoned, do you find yourself mixing rounds? Do you choose music from different rounds to match with choreography from other rounds? What do you find makes the best mix for a class?

Just curious on this. Personally I'm finding 42 a bit repetitive and am interested in how others structure their playlists.

I don't know how seasoned I am, but I do mix rounds. I pick a new segment (right now, it's punches) and introduce that into the "old" round. Next week, I'll introduce the new kick section into the "old" round, etc., until it's all entirely the new round.

I put the music on my phone, and currently use music from Round 44 with a mix of choreography from 2 rounds. As the music is all 32 counts, I find it doesn't really matter. And for the cooldown, you can get creative.