I’m thinking about flying 30 december till 2nd to to Florence because very cheap. Now the 31 till 1st is every winebar/restaurant closed or some open but need to do reservation ? Any life outside on streets ?
There are several musical events in the main piazzas, with a mega concert in the Piazzale the last 2 years.
This article has the info from last year's events - https://www.visitflorence.com/florence-events/new-years-eve-in-florence.html
While we don't have any info for this year yet, it gives you an idea of what takes place. The last 2 years the events have been in the same locations, and the genre of music for each place stays the same - like classical in Pza della Signoria, gospel in Pza SS Annunziata, etc..
We will update that page in December, since that is when info on new year's starts coming out.
As far as wine bars and restaurants EVERYTHING stays open, and many offer a set menu/evening events with limited seating so require reservations. You can wait until you are here if you're here for a few days before the new year's eve to book if you don't know where to go but if you can, search for restaurants you want to try and then pick one and book at that place (a week or 2 before).