The 4th Jam Collective session is coming up this Sunday and I'm barely half way through mixing the last session. That's partly my fault - I haven't really made time for it until now - but there are other factors. The big one is that we had a 5 hour session last time. That's over 4 hours of audio to work on!
I don't need to listen to the whole session from beginning to end: Normally, once I have a good basic mix, I only really need to cut the tracks where they begin and end, with a cursory check to make sure the levels are still OK.