Start with function
Circular design begins with what people need an object to do.
A service, not a unit
A product is one way of providing a function. Start by describing that function and the conditions in which it is needed. This makes it possible to compare durability, shared use, repair and replacement on a consistent basis.
The business connection
Changing ownership or extending life changes responsibilities as well as revenue. Maintenance, returns and customer support need an operating model. A circular proposition must be useful to the customer and workable for the organization.
A bounded first question
Choose one product family and one customer need. Identify the evidence needed to compare alternatives. A focused question creates a better starting point than an organization-wide promise with no decision attached.