Architects, house designers, and kitchen and bath designers can convert your wish list into a detailed plan with a rough budget. In general, you’ll benefit the most from hiring an architect or house designer if you need a lot of design work — for a big or complicated addition, or to tie in significant changes to more than one room. Architects have the most education and training, but the difference between a qualified designer and an architect often comes down to the latter’s knowledge of engineering, which, for most home improvement projects, is not an essential qualification.