A life cycle comparison should compare the same transport function, not just packaging labels. If the functional unit, route and product conditions differ between single-use and reusable options, the results are not comparable.
State the boundary and function. For example, define the functional unit as a quantity of delivered product and state that both options carry the same load to the same destination. List whether container production, preparation, washing, return travel, repair, loss and end-of-life treatment are included.
Link operational inputs to records. For reusable containers, use observed trips, washing water and energy, return-vehicle distance and load factor, and damage and loss records. For single-use packaging, document packaging quantity and the actual disposal route. State each value's source, measurement period and whether it is an assumption or observation.
Compare scenarios separately
Change one variable at a time, such as lower return count, a different return load or another end-of-life route, and recalculate. Break-even is not a universal trip count; it depends on the data and system boundary. Keep the input table with the result so new field records can update the calculation.
