Why battleships normally fired broadsides

Were full broadsides exceptional, or did battleships usually fire their guns together?

Broadsides were standard because they maximized hit probability; firing at will was more likely at close range under local control.

Firing full broadsides, or as many guns together as possible, was normal practice because it maximized the chance of a hit. Ships did not generally imitate the independent firing familiar from games. At sufficiently close range, individual mountings could fire at will under local control. Even then, a central director maintained the overall fire-control plot, preserving coordination while the guns fired more freely.