Ply is a conversation about burst, stacking and monsoon humidity — not a number to minimise on a spreadsheet. Light garments may travel happily in 3 ply. Glass, oils and export mixed loads usually ask for 5. Heavy engineering and long warehouse stacks often need 7 ply or a better flute, not just more paper.
We talk through ECT, flute profile and print coverage before we lock a board grade. The aim is a carton that looks like your brand and still cubes cleanly after 800 kilometres of Gujarati and national highway.