In the absences of such contracts, unexpected mistakes and misunderstandings can occur, costing both extra time and money. California law has required architects to write up specific agreements since 1996, for just this reason. It is often easiest to use the standard form, provided by the American Institute of Architects, or the abbreviated standard form.
An architect’s fee is not of one standard, and will vary from project to project. Architects will usually charge according to a time-based fee, a fixed fee, or by percentage of construction cost fee (the overall construction cost multiplied by an agreed-upon percentage). This is one of the main reasons it is extremely important to make sure you and your architect make the contract very clear, and avoid any money discrepancies. Go over the contract together carefully and make sure that all terms and agreements are of a mutual and specific understanding.