How often do prices update?

A coin’s price is fetched every time its turn comes round in the rotation, and never more often than every nine seconds. With a few coins and short screen times that is a fresh price every visit; with twelve coins at thirty seconds each, every six minutes. The server behind the ticker renews its price cache every few tens of seconds, so what arrives is at most that old. Twenty-four-hour figures are rolling, counting back from now. See How often prices refresh.