Really an excellent question. As noted above, it's a bit dependent on where in the world you're looking, and what kind of battles (ie, land or sea) and in what time periods. Generally speaking (pun intended, and I mean, in the broadest possible sense as well) a pitched battle was decisive for an entire war. They were very rare, and often consciously avoided due to the immense risk. Some of the most brilliant war leaders in history actually intentionally forced pitched engagements to quickly defeat logistically superior foes. Examples: Genghis Khan, Subotai, Alexander the Great, Hannibal Barca, and Cao Cao (who ironically got spanked in a decisive fight too). Siege warfare was the expectation in western europe and the near east for a long time. Taking castles meant taking land meant expanding logistical base. This pattern is broadly true in the far east as well, with the caveat that the Chinese, especially during the warring states period, skirmished and battled in very large (possibly exaggerated) numbers.