The first tenet in lean thinking is to:

Select one:

a$.$ Ensure that flow within a process is simple, smooth, and error$-$free, thereby avoiding waste.

b$.$ Identify, study, and improve the value stream of the process for each product or service.

c$.$ Strive for perfection.

d$.$ Produce only what is pulled by the customer.

e$.$ Specify precisely what about a product or service creates value fro the customer's perspective.