There are many professionals that can help you with projects on your house. If you are just rearranging the cabinets and appliances in your kitchen, a kitchen designer may be right for you. If you are redoing interior or exterior finishes -and know what you want- you can often work directly with a contractor. The time to hire an architect is when any project involves changing part of the permanent structure of the house (walls, windows, doors etc). Architects are trained to keep in mind all the different aspects of a project- balancing how it looks inside with how the exterior will express the whole. The architect's job is to make sure that it will all work together, coordinating the structure, plumbing, electrical and finishes so that the finished product works well and looks great.
Architects are professionals who must maintain their professional license in order to be allowed to be practice architecture. For more information about working with an architect look for the Homeowner's Project Handbook in the directories section of: The Boston Society of Architects website.