Hello, we are visiting Florence in early October. All the blogs/articles are saying we should buy Accademia and Uffizi tickets in advance online. But how far in advance should we book? The day before? A few days? Weeks? Months???
Early October is still a busy time so I would recommend booking tickets for both museums ahead of time.
You don't need to do that right now but, at the same time, once you know your precise dates in Florence, I would say go ahead and book them, either online or by phone. That way you can build your itinerary in Florence around those visits. I definitely would not recommend trying the day before, at that point you likely won't find any tickets left from those sold online - you will only be able to visit by going straight to the museum and getting in line. If you're working on your itinerary already, why don't you check the availability of tickets for your dates? If you already see there are time slots that are not available, it gives you an idea of how busy those dates are and whether you should go ahead and book or wait a bit.
My personal recommendation is just to book once you know your dates, as there really also isn't a good reason to wait (unless you're waiting for something else to be confirmed for your travel plans to be confirmed). Tickets, once bought, are not refundable.