This is one of the liveliest little neighborhood squares in Florence. Every day you see familiar faces milling around the square, from fashionable international types to neighborhood artisans to bartenders to the rugged guys hanging around the fountains.
Day or night there is always something to see in Piazza Santo Spirito. It's a prime people-watching location. Particularly in the summer, the square is always busy, with bar patrons spilling out into the piazza or miserly locals grabbing a beer or bottle of wine from a nearby minimarket to enjoy on a bench. Mornings are produce market time!
The square's giant flea market is generally held on the second Sunday of the month, but sometimes you'll find surprising pop-up events and markets.