How far in advance can I buy tickets for Uffizi and Accademia?

I'm not completely positive, Joel, but I'd start checking the b-ticket site (that's the official ticketed site for most of Florence's museums, duomo complex aside) right around the 1st of the year. I'm going on the fact the tickets are currently available all the way through December 2022 so quite far in advance.

https://www.b-ticket.com/b-ticket/uffizi/default_eng.aspx.html

Be aware that tickets are non-changeable and non-refundable so be sure of your dates when you purchase, OK? :O)

glad you are getting them in advance, it is the only way to go.
We kept checking every few days until our dates came up on the website.
You didn't ask this, but I would only go to one museum a day. We liked going at 10:00 so we could take our time in the morning and then after the museum we could walk around for a little while, take a siesta in our hotel in later afternoon and then go out before dinner to see some more sights, have a late dinner like Italians do and then gelato!
Rick Steve's audio app has great audio tours of both the uffizi and accademia as well as a good walking tour of Florence.

I had the same question, except we plan to visit the Uffizi the end of February 2023. The website now only goes up to December 31 ,2022. I sent an email to the Uffizi (translated with Google into Italian) and they answered:
"We inform you that there are currently no dates for 2023 tickets yet. We invite you to keep up to date by consulting our website."

FYI, my original query in English went unanswered.
Susan

Consider the Walks of Itay Uffizi tour. Choose the day the museum stays open late, I think it was Thursday when we visited.

With WOI, you get skip the line tickets. Our guide had a Masters in Art History and for us, the added insight and his taking us straight to the "best of" areas were a plus. Afterwards, we stayed late and explored other areas on our own. The size of the group is held to no more than 12. There were just 6 of us when we were there in December. May will be busy.

I agree with the other poster who limits themselves to one museum a day. It's easy to get burned out, especially in larger museums.

If you've never been to Florence you are in for a treat. The first time Deb and I were there was on a school trip together in August 1966. She was 14 and I was 15.

We did the Accademia on Day 1, Ufizzi and Pitti Palace on Day 2. We did not find this to be overly tiring. Accademia was far more crowded, even in early Oct.

I checked the Uffuzi's website and was surprised they have tickets available for tomorrow exccept from about 9 AM to 11 AM. I am planning a trip to Florence next month and looking for that sweet spot of not booking to early or too late for everything. Post covid I am thinking about this more. If I need to actually use my travel insurance, I personally want as few things as possible to seek reimbursement for. I also have other circumstances that make me worry about a potential trip cancelation, so I guess we are all different in that regard.

Just an FYI...We were just there last week. We had tickets for a 9am entry and they decided to have a staff meeting and would not open until 1030am! No notice at all. We took advantage of the 90 minutes to walk around but ended up in a line for about 30 minutes with a lot of upset people. Still worth visiting. We did the Academia that afternoon and there was no line.

I bought both tickets online about 3 months in advance.

@Joel @Susan: I just checked their online ticket website (https://webshop.b-ticket.com/webshop/webticket/eventlist); they just open tickets for sale up to Feb. 28, 2023. It appears tickets are available for booking about 4 to 4.5 months in advance.
So if you are visiting in early May; start checking their website around early January.