Product logic wearing an interface.

Most businesses need two or three of these, not all six. Which ones depends entirely on where your customers currently get stuck — and that's usually obvious from the questions your sales team answers most often.

Every example below is a tool we built for our own retail business and still operate today.

Five separate tools that each ask the same six questions is five abandoned sessions. The architectural decision that makes the difference is storing the customer's answers once, in a shared profile, and letting every tool read from it.

Each tool stays short. Collectively they behave like one system that remembers you.

A room measured in the planner is still measured when the customer reaches the screen finder an hour later.

Rarely on the rendering. Almost always on the commercial rules — the combinations that can't be built, the discount that applies differently than anyone wrote down, the configuration that reaches the warehouse in a form nobody can pick.

One real example: a volume discount that counts units rather than distinct products. Trivial to state, easy to implement backwards, and wrong in a way that only shows up in the margin report months later.