First, you should decide if you should collect purchase orders or bills of materials / product specification documents. A purchase order is a receipt for a big, aggregate purchase of materials. A factory might purchase 5,000 kilograms of steel to make 20,000 canteens. The document showing that 5,000 kilogram purchase is a PO.

A bill of materials or product specification document will come from your product or engineering team and is the per unit recipe for making products. In the same case, it might show that a single canteen is .25 kgs of steel, plus .1 kgs silicone.

If you have purchase orders, it might not matter that you make many different product types. You already have these nice, aggregated material purchases that are ready for footprinting.

However, looking at a stack of 100s of BOMs can be overwhelming. In this case, you should decide on representative or typified products that can capture several SKUs. Yes, you may have 20 SKUs that are canteens, but in reality, they're not materially different and you can build a single, typified BOM called simply and generically, "canteen".

Lastly, a product like a jacket might have 200 components, but on the whole, it's mostly nylon and polyester. If you're looking at a long product list, understand that you can typify your products by their materials that are most significant by weight. The BEE will estimate materials that are less significant - things like coatings and small trims should be captured in your initial estimate and if you're not capturing them in your data collection process, that's ok, but you should rely on our estimates.