Two ships, or a ship and aircraft or submarine have a slightly better capability than a single ship or aircraft, and under some circumstances a group of several units can provide an extended capability. The point is that naval forces can be organized into operational groupings for specific missions or tasks. To be able to respond to the full range of likely situations the state needs a fairly wide range of capabilities. Yet, a limited degree of specialization is still needed to keep costs under control. For instance, where one specialty can be shared by all ships in the task group it may be cheaper and more efficient to integrate a specialized vessel or aircraft into the group.
Logistic support is one such example.
It is far better to centralize fuel and other support rather than increase the size of frigates and destroyers to give them a 30-day endurance. The Canadian Navy routinely operates under both situations, and has done for many years. Because it is the most efficient way of operating. Maintaining national task groups gives one the capability to respond to a wide range of situations at home or elsewhere. Also, by training within a task group concept, single ships can be sent to multinational formations with confidence that they will perform effectively in the partnership.