Two churches in Florence. Santa Croce has 7 tickets and tours to book; Medici Chapels has 4 tickets and tours to book. The table and the two notes below put them side by side; the full pages have what to see, the ticket and the timing for each.
One ticket covers the church, the chapels, the cloisters, the Pazzi Chapel and the museum in the old refectory, and it is bought at the door or online for a small saving in queueing. Booking matters only in high summer. An audio guide is available and useful, since the chapels are numerous and the labels are brief. Guided tours with an art historian cost several times the ticket and are worth it if the Giotto frescoes are your reason for coming, because the two chapels in question are behind a rail and need pointing out.
The ticket covers both chapels attached to San Lorenzo: the Chapel of the Princes, a vast domed octagon lined in coloured marble, and the New Sacristy, Michelangelo's room with the ducal tombs. It is a state museum, so entry is included in some Florence museum passes, and free on the first Sunday of the month, which is also the busiest day. Buying online with a timed slot is worth a small fee in season. Guided tours cost several times the ticket and are worth it only if you want the sculptures read carefully.