FirenzeCard

I'm headed to Florence in a few weeks and planning to buy the Firenze Card once there. However, I was able to call the number listed and make reservations for both the Uffizi and Accademia, just mentioning that I will be a Firenze card holder when I arrive at the sites. So while I can't speak to the experience yet, you are able to call now and make your reservations without having to purchase the card itself ahead of time.

We had the Firenze card and still stood in line for over 2 hours. This was in 2017 so maybe the process has changed since then.

NursCyn, the process has recently changed. Holders of the card now have to make advance, timed-entry reservations for both the Uffizi and Accademia. Advance reservations are also required for the dome of the duomo, can't be made until card holders are IN Florence, and can be sold out at that point.

jojo, if you know what day/time is preferable to you, I'd go ahead and make your reservations now to be sure of getting what you want.

Does the advanced time reservation allows you to skip the lines? Just want to be prepare on how long the wait would be.

It allows you to skips TICKET lines but not security-check queues. No one can skip those. You might want to arrive at the museums you have reservations for 15 minutes before your appointed time.

There are no "priority entry" lines just for the pass at the duomo complex. You'll collect a ticket at the ticket office and then use the same queues as people who bought tickets in advance. The main body of the cathedral itself is free so everyone stands in the same line, which can be long.

From the Firenzecard website:
"For the visit to Baptistery, Dome, Bell Tower, Cryipt and Opera del Duomo Museum you have to go to the ticket office in Piazza San Giovanni 7, you have to show your Firenzecard and to collect the free ticket to put in the automatic turnstiles."

Other museums may or may not have separate priority-entry lines for the pass but most aside from the Uffizi and Accademia will not have long queues anyway. Some additional Info on each museum can be accessed under the "Museums" tab on the website: click the name of any on the list to pull that up.