Being disabled (needing crutches) in Florence is not easy. The pavement is often narrow or non existent so walking on small surfaces or pavement is a must. Furthermore, there are buildings one cannot access because of their age. One can think of the Duomo and the Campanile. The most beautiful views are simply very high up. The buildings are ancient and narrow, and because of this, installing an elevator is impossible. One should add that the cars go very very fast. In our opinion faster than they should. This means that crossing the road is very dangerous and one has to move very fast if a pancake is not what one wants to be in the near future.
However, many other buildings, notably the museums remain accessible to people with this kind of disability. One can think of both the Palazzo Vecchio and the Palazzo Pitti which both have an elevator. Many museums have one too, like the Museo dell'Opera del Duomo. The piazzale Michelangelo, which is high up, has good steps and a railing so although it is a long walk, it is accessible.