The commercial starting point
Find the growth opportunity that the current range does not serve
Product expansion can make a range more useful or simply spread the same demand over more variations. I start by mapping the products customers already buy, the alternatives they compare and the reasons an existing offer fails to fit. That separates an unmet need from a competitor feature your business does not need to copy.
For US Amazon and retail work, the decision also depends on landed economics, channel roles, minimum commitments and replenishment. A promising demand signal is not enough if the product creates an unattractive stock exposure or cannibalizes a stronger item. The brief brings commercial and operational assumptions together so product, finance and marketing can evaluate the same opportunity instead of defending separate forecasts.