Florence Dec 20-26 - concerned about itinerary

When we lived in Europe one of the first things we had to learn was the variable but early closing hours of many things, even in big cities. Religious holidays in Europe in general are much less commercial than in the US, and closings for all of Sunday (and for many sites on Mondays) is common. LOTS of people will be off visiting their families so trains/buses can be very crowded. You really need to check on each site's website for its opening hours during your visit. Adjust as needed. Things may be open Christmas Eve morning, but don't count on the afternoon. Bread will always be available in small shops - get preferred locations from the people from whom you are renting the apartment. And, you should look into booking dinner reservations early too. For five people with an apartment over Christmas, but maybe just for myself, I would stock up on wine and food specialities (fruits, cakes!) and be prepared to graze on an elegant buffet of delicacies throughout Christmas Day.

A lot of shops - but not all - will be open on Sunday 22th. Most shops in Florence are closed on Monday morning and so it is likely to be on Monday 23th (I seem to remind that Siena has a different weekly half-rest but not really sure). If you need restaurants on the night of 24th and on Xmas day be sure to reserve well in advance as really good ones will be fully reserved already a couple of weeks in advance. Xmas day and 26th are almost dead days - museums are likely to be closed on 25th but most should be open on 26th.