Embedded complexity must be viewed as an investment when making design choices on recycle, reuse, or beneficial disposal

A complex system contains many constituents and they interact nonlinearly and they are interdependent. It also possesses structure spanning several scales and the system is capable of adapting to the new environment.

A good example of a complex system is biological systems. Human body and mind has many constituents and they interact seamlessly in different dimensions and in different time. They are certainly capable to adapt to a new environment.

One of the most complex man-made systems is an aircraft carrier. US Navy has an extensive maintenance and overhaul plan to keep them operational for a long period of time. In fact, one of the oldest ships in US Navy is USS Enterprise (CVN-65) which was commissioned in 1961 and recently (2012) retired from service after 51 years of useful life.

It is appropriate to consider the complexity of the system before deciding whether to reuse, recycle, or discard. For example, complex systems such as large ships as explained above should be kept in service as long as possible while power train systems within the ship can be refurbished to extend its life. A simpler systems such as a door in a ship can be recycled while a simple system such as a wash cloth can be discarded.

The hierarchy of reuse, recycle, or discard depends on the complexity (i.e., energy, resources required to produce it).

If a simpler system can achieve the same function as a complex system, from a sustainability point of view, the simpler system is better. For example, attacking terrorist cells, simpler systems such as drones and missiles could be used rather than using fighter jets and troops.