Whether or not a player turtles depends on certain factors, such as the stage of the game, and the civilization's bonuses. Also, it depends on whether the map features enough chokepoints, to minimize the cost in stone of defensive structures. The utility of turtling inevitably diminishes when siege weapons start rolling on the field, especially Heavy Catapults, but it can still be useful when preparing to build a Wonder, with the defensive structures existing to delay the enemy for as long as possible, until it stands for two thousand years, and the player wins the game.