The fabrics and the notions are chosen together
It starts with the fabric — and specifically with deciding which fabrics belong together. Once that pairing is settled, everything else has to be chosen to match: the zipper colours, the webbing, and the hardware finish, whether that's gold, rose gold, silver nickel, gunmetal or bronze.
All of it gets laid out together before a single piece is cut. That is the whole creative decision, made up front.