I’m out of votes but regarding what happened at the Blue Ridge Rock Festival this year, this feature would be so crucial. 2 days 1/2 out of 4 were cancelled, and you can only mark the whole thing as cancelled or not cancelled at all. + there were already 4 duplicates last time I checked, with different lineups, because people only add what bands they saw or played, not all the bands planned for the festival. I wish mrblond’s idea was incorporated!

I would love to have the option to choose to which day(s) of a festival I went but I wouldn't like to have it counted more than once. To me personally it's one event (that's why it's a festival and not several single concerts) I attended and I don't want it to have that counted twice or even more.

This is related to one of the above posts, so I apply my comment here too:

"...Yes, I think the multiday entries must be stopped and the existing ones must be divided in single day sections. Moreover, for big festivals with more than one stage on the site, even the single day entries should be divided per stages.
Years ago, I've developed a really clean system for adding festivals in concert data-bases like this. I would share it here if the hosts demonstrate willingness to tidy this archive up."