At first glance, this may seem to be contradictory to Make it less complex, but there is a big difference between usefulness and complexity. Taking advantage of a natural, or logical extra use for a product will not only make the product more desirable and interesting, it will also help reduce the amount of products headed for landfills. Multiuse products can reduce consumption and increase convenience.
Example: The shape of the flat-head screwdriver on most pocket knives has been cleverly designed to also function as a bottle opener. The usefulness of the device has increased with no added material or complexity.
Watch out: be careful not to let added usefulness detract from the functionality of the product. Poor functionality can lead a consumer to abandon the product altogether for a better functioning model.