An architect usually handles the drawings for a client. They will need to use the IRC as they draw to make sure the drawings in accordance with code. The design phase is crucial because even if they draw something the client may want on the home it is the job of the architect to make sure this request can be incorporated architecturally to meet code requirements. As a builder or remodeler, you will need to check drawing for accuracy and make sure any code deficiencies are corrected prior to moving the home build or remodel forward. If the plans go unchecked, it can be detrimental as the client may ultimately have to make unwanted changes as the plans move forward to the engineer or building department based on requirements.