Holford Engineering's five principles of lean
1Accurately specify the value from the customer's perspective for both products and services.
2Identify the value stream for products and services and remove any non-value-added waste along the value stream.
3Make the product and services flow without interruption across the value stream.
4Authorize production of products and services based on the pull from the customer.
5Strive for perfection by constantly removing layers of waste.