Whatever works for you. I used to pull them down new years day, then decided that sucks because it's around the time I usually go back to work. Now I pull it down whenever it works for me. This year that means tomorrow (and the following days since it takes a good few days to pack it all up)
I'm planning to stay lit up until NYE so that any stragglers or other ACL members who couldn't get to see it and say hello get a chance to see once they close down.
I run up to NYE with non Christmas songs, and then do a NYE countdown and play auld lang syne at midnight, then they go off. Wait for a dry spell and then pull it down, repair things as I put them away, and up in the roof.