Or buy my own carpet... Builders get these questions a lot. Here’s why a Yes answer is seldom in the homeowners’ best interest. It’s not unusual for new-home clients to ask their builder to use a trade contractor with whom the clients (but not the builder) have an established relationship, or to let them buy their own plumbing fixtures or other items. Most builders won’t agree to this. Sticking to familiar subcontractors is a policy that’s in the best interest of the builder and the homeowners. The reasons have to do with the business relationships between builders, suppliers, and subcontractors.